


looking out on the day of another dream

by PsychoLimbo



Category: Invader Zim
Genre: Alternate Universe - Creatures & Monsters, Alternate Universe - Merpeople, Dib is still a human here, Enemies to Friends to Lovers, Fantasy AU, Friends to Lovers, Implied/Referenced Child Abuse, M/M, Mermaids, Merpeople, Minor Injuries, Minor Violence, Modern Fantasy AU, Mystery Elements, Professor Membrane's A+ Parenting, Selkies, Seriously he's kind of terrible, Siren!Zim, Sirens, Some comedy, mythical creatures
Language: English
Status: Completed
Published: 2020-05-14
Updated: 2020-05-24
Packaged: 2021-03-02 23:15:42
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 26,338
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24184996
Author URL: https://archiveofourown.org/users/PsychoLimbo/pseuds/PsychoLimbo
Summary: Zim the siren and Dib the human have been playing a heated game of cat-and-mouse ever since they met as young children. It's so intrinsic to their relationship that neither of them ever considered being anything else to each other.But when Zim comes across Dib sinking to the bottom of the sea, he doesn't have the heart to leave his rival for dead.Thus begins their mutual realization that perhaps, they don't need to hate one another.
Relationships: Dib & Gaz (Invader Zim), Dib & Professor Membrane, Dib/Zim (Invader Zim), Gaz & Professor Membrane, Invader Skoodge & Zim
Comments: 59
Kudos: 436





	1. ocean eyes

**Author's Note:**

> Unlike the last mermaid fic I attempted to write for the bnha fandom years ago, I intend to finish this one! This was originally supposed to be a oneshot but as I expanded on the world, I realized that this wouldn't reasonably fit into a oneshot. So it's gonna have 3 chapters :)
> 
> Hope you guys enjoy it!
> 
> Title is from [On Melancholy Hill by Gorillaz](https://youtu.be/04mfKJWDSzI)

* * *

The day it happened was an otherwise calm one.

Hunting was good, the sun’s rays ensured the water was pleasantly warm, and the waters were lazy enough that one could fall asleep under the water and not have to worry about being carried away. All in all, nothing of note should have happened.

Unfortunately though, something _does_ happen. 

As Zim checks the contents of his hand-woven seaweed net, he’s alerted to the sound of a distant splash. Antennae pricking, the young siren turns his head in the direction of the sound. For a moment, he considers ignoring the splash entirely. However, curiosity—and the prospect of a good meal—win out over his self-preservation, and he swims closer to the sound of something struggling under the water. 

Before long, Zim’s sensitive eyes pick up on the vague shape of a human thrashing about beneath the surface, sinking ungracefully deeper. Zim’s lips curl back into a hungry grin. It’s rare that a siren comes across such a find without having to put in effort, and Zim darts close with his claws outstretched.

Before he makes contact, though, he freezes.

He knows this human. 

Zim retracts his claws slowly. This is the Dib, a human who’s been a source of entertainment to Zim for several years. They may have never exchanged words face-to-face, but they’ve played an unending game of cat-and-mouse since the day they first caught sight of one another. Zim never imagined he and the human boy would’ve ever been this close to one another again—- not after _that_ incident a year ago—- but here they are.

And judging by the way the Dib thrashes about, he never learned to swim. Zim feels a pang of disdain that quickly turns to alarm when Dib’s movements grow sluggish. .

Zim hisses in frustration, grabbing the Dib by his strange, warm forearm and powering away from the dock the boy must have fallen from. As easy as it’d be to just drag him back to the surface, Zim can’t risk being seen. He’s not sure whether or not there’s a human onlooker at the shore, and he has enough self-preservation to keep himself reasonably hidden.

As Zim rounds a curve in the shoreline, the Dib begins to struggle. His weird five-fingered hands twist and claw at Zim’s webbed hand, but the siren doesn’t let go. He has a destination in mind, and no stinking human is going to deter him from that. 

Finally, Zim breaches the surface, dragging the Dib with him and shoving the boy onto dry land. Zim follows, hauling himself up out of the water and watching as the Dib vomits saltwater. 

Zim brought them into a cave, one which can only be accessed by a short underwater tunnel. It’s almost completely dark, save for the thin beams of natural light that filter in from cracks in the rocky walls. Shallow tide pools dot the sandy floor of the cave and reflect shards of sunlight onto the water-smoothed walls. All in all, Zim considers it a perfect hiding place for a young siren and his captive human. 

Once the Dib finishes emptying his body of saltwater, he turns his head and yelps at the sight of Zim. The siren chirps in amusement, and he makes a show of flaring his brilliant fuschia fins and baring his two rows of jagged teeth at the young human. The Dib lets out a cry of alarm, scrambling backwards across the sand until he topples ungracefully into a tidepool. The boy makes another startled noise, pulls himself from the tide pool, and tries to put more space between Zim and himself. 

Unfortunately, the cave is rather small, and Dib’s back crashes into the wall a measly six feet from Zim. Zim hisses, an intimidating noise in the enclosed space of the cave, in the hopes that he’d give the Dib a mild scare for fun’s sake.

To Zim’s surprise, though, the human pup stares at Zim with wide, fearful eyes and presses himself into the wall as much as he can. Zim relaxes his lips to hide his fangs and lowers his fins. Now that he’s really paying attention, his antennae pick up on the frantic thumping of the Dib’s heart and his hyperventilating breaths. Not to mention, the human’s soaked clothes cling to his lanky frame, and the chill of the cave combined with his terror make the Dib tremble uncontrollably.

With a pang of guilt, Zim swallows and backs up to give the boy some space. Even so, the Dib stays pressed against the wall with wide eyes. Zim lets out a mildly irritated series of clicks before forcing his vocal cords to form human words.

“Zim… safe. Zim will not hurt you,” he says in a clicking, chirping dialect.

The Dib jumps, breath stuttering. Then, after a short time, the boy speaks in a hoarse voice. 

“I don’t trust you.”

Zim hisses involuntarily, and the human boy lets out a sharp cry of fear. Dragging a webbed hand down his face in frustration, Zim glares at the roof of the cave. “That is fine, human. Just cease your infuriating cowering.”

“I’m not _cowering._ ”

“Then what do your fellow _humans_ call that…thing you’re doing right now?”

Dib blinks owlishly, then straightens up and folds his arms across his chest in defiance. “Nothing. I’m not scared.”

Zim smirks in amusement, antennae twitching. “Your heart rate says otherwise.”

“Stop checking my pulse, you fish-faced freak!”

“At least I can swim, Dib-feets!” Zim retorts, and that seems to hit a little harder than their current light banter.

The human boy’s scowl fades, and he lowers his gaze to stare at his sand-caked feet. “It’s not like I don’t _want_ to swim.”

“Then learn.” 

Dib glares at him. “My dad won’t let me!” he snaps, “He’s strictly forbidden me and my sister from even _looking_ at a pool!”

“Zim is unsure of what this “pool” is,” the siren begins, “but why does your parent prevent you from learning to swim?”

Dib kicks at the sand. “My mother was apparently lost at sea, so dad doesn’t want us anywhere near any body of water.”

“Human parents control their pups to such a degree?”

“No, but every once in a while you get crazy controlling parents like my dad,” Dib mutters, “Also we’re called “kids,” not pups.””

“Semantics, who cares?” Zim groans, “Where was your parent when you fell into the sea just now?”

“At a work conference. He left me with this thing so he can monitor where I am, but we both saw how well that worked out.” Dib sighs before raising his right arm to show Zim a white and blue bracelet wrapped snugly around it. 

Zim pulls himself across the sand, stopping close enough to poke at the bracelet with a clawed finger. He cocks his head at his own reflection in the shiny surface, then asks, “Why did you fall into the sea, Dib-feets?”

The teen boy’s face darkens. “Don’t wanna talk about it.”

“Too bad, human, you will tell Zim or I’ll leave you here to drown when the tide comes in!”

Of course, Zim has no intention of leaving the Dib here, but the boy doesn’t need to know that. And the threat works. Dib mutters something incomprehensible before letting out a noisy groan and snapping, “Okay, fine! Kids at school like to beat on me for being weird and they chased me to the docks from school! And they threw me in! Who cares?!

“Ha…hell, maybe you should’ve just left me to drown,” Dib says bitterly, “Not like anyone would’ve missed me anyways.”

Zim stares at the Dib in shock. 

A clawed hand darts out to grab the front of the Dib’s shirt. 

Zim yanks the boy close, close enough to feel Dib’s hot breath on his face, and bares his fangs. “I will _not_ have my greatest enemy talking like that. Do you hear me? The only creature allowed to kill you is _Zim._ Am I clear?”

“Oh, fuck you,” Dib growls, “You don’t get to act like you _care_ about me after the years of fights we’ve had! We’re not friends, and you should’ve left me to die when you had the chance.”

Zim hisses savagely, hand shaking as he struggles not to slam Dib back against the wall of the cave. He closes his eyes, takes a deep breath through his nose, then lets it out slowly. His fingers slip free of the Dib’s shirt. The young siren reaches up with one hand to absentmindedly fiddle with one of his antennae as he searches for the proper words.

_Wait. I have the perfect opportunity here to get what I want._

Zim grins. 

_I will pretend to be his friend in exchange for human trinkets for my collections_. 

“I now understand that our relationship hasn’t been the most…” Zim trails off, settling into his remorseful act like a second skin, “... _healthy_ thing for you and I, but Zim is willing to try again.”

“You sound like my dad.”

“We’re both 15 years of age, you smelly meatbag!”

“I mean with the whole “trying again” thing,” Dib clarifies with a sigh, “Look, uh…do you really mean that? That you’re cool with trying again?”

“Yeah, yeah, I’ll teach you how to swim and all, on one condition!”

“ _There_ it is.”

Zim swipes his tongue hungrily over his lips. “I require payment in the circular human treat! The sticky one with a hole in the middle!”

Dib blinks. “Oh. Sure, I can bring you donuts.”

“Excellent! We will meet up again tomorrow night! And be sure you do not forget the donuts!”

“Got it. Now, uh…do you think you can take me back to the beach?”

“Only if you promise to bring me more sweet-stuffs with the donuts.”

Dib rolls his eyes and throws his hands up in exasperation. “Fine, whatever! I’ll buy you, like, a fudgesicle or something next time I'm at the corner store!”

"This pleases Zim,” Zim hums, “We have a deal, Dib-feets!”

* * *

The following evening, Dib sits at his desk as he tries fruitlessly to pry the Membracelet from his arm. The window is open, blowing the salty scent of the ocean into his room, and Dib feels like he’s going mad. 

With a string of curses, he tries forcing a flat-head screwdriver into the seams of the Membracelet. He nearly manages to pry the casing open just a bit, but the screwdriver slips and stabs Dib in the forearm. He curses loudly, dropping the screwdriver and clutching the darkening bruise on his arm. 

Once the initial pain has passed and subsided into a dull ache, Dib once again glares at the Membracelet. In his head, he hears the commercial jingle for the stupid device:

**_Membrane Labs Membracelet: Who wants a better everything?_ **

Dib hisses sourly through his teeth. “Yeah, right. “Better everything”, my ass.”

He almost wants to scream, or cry, or something, _anything_ , to get rid of the frustration that chokes him. Dib runs his hands through his hair and paces his room. 

He paces until his mind wanders back to yesterday.

As terrifying as it was to be at the mercy of the sea, sinking to the ocean floor, it was also _intoxicating._ Dib’s been land-bound for years, forbidden from even visiting a swimming pool so he wouldn’t be tempted to visit the ocean. So finally experiencing the feeling of water caressing his body, making him weightless and breathless at once, was almost overwhelming. Dib glances out his window at the ocean a quarter-mile away. 

The ocean whispered to him before, but now? Now, his chest physically _aches_ with the distance. 

Dib tugs at his hair and begins pacing again. 

“God, I’m losing it,” he mutters to himself, “What the fuck is wrong with me? What the fuck is wrong with _dad_?”

It’s then that he hears a high-pitched whistle from the beach. Dib lets go of his hair, head swiveling to glance out the window at the setting sun sinking into the sea. He bites his lip. 

_Zim._

When Zim had returned him to the beach, the siren demanded Dib meet him at the rocky part of the shore the following evening. Some part of him thinks this is a bad idea, that Zim is secretly planning to drag him to his death, but even with that possibility, Dib just wants _something_ to ease the hollow ache in his chest.

With an exasperated groan, Dib snatches his favorite blue hoodie from where it hangs over the back of his desk chair and slides on a pair of worn-out flip-flops. 

Before he moves towards the open window, however, he takes a minute or two to sneak upstairs to the lab and snatch a stale donut from the box the professor left on his desk. Once he’s gotten Zim’s requested “payment”, he makes his way back down the rickety wooden stairs to his room. 

“Dad’s gonna _kill_ me _,”_ he mumbles, but crosses his room and climbs out his bedroom window anyways. 

Once he’s outside, he quietly slides his window shut and climbs down using the little ledges he’d carved into the brick wall himself over the years. It doesn’t take long—he’s climbed this wall countless times in the past—and the moment his feet hit the ground, he’s bolting across the yard and vaulting over the back fence. 

He’s not sure how he manages to run the quarter-mile to the beach at a dead sprint, but he can’t find it in himself to care. All he knows is that, at least for a short time, he’s going to be able to stand in the shallows, searching for shells and starfish without his dad breathing down his neck. And that thought brings a huge smile to the teen’s face. 

By the time he reaches the sandy shore, Dib’s legs have been chafed raw by the saltgrass he’d run through, and his sweater is stained with sweat. Chest heaving, Dib slows to a leisurely jog and follows the shoreline to the rocky cliffs and caves where Zim had demanded they meet.

As he clambers over a massive piece of driftwood, Zim’s chirping voice rises above the sound of the crashing waves. “About time, Dib-feets! You kept Zim waiting!”

Dib stops for a moment atop the log, taking a moment to actually _look_ at Zim.

It’s been a year since the two boys have been this close to one another, and thankfully, this particular time is under much better circumstances. Zim’s iridescent green scales reflect the sunlight in a dazzling display, but Dib can’t help the way his eyes linger on the wire-thin scars that zigzag across the siren’s tail, abdomen, and arms. Before Zim can notice him staring, however, Dib climbs over the log and hops down on the rocky beach.

“Well, I’m here now,” Dib shoots back, approaching the deep, water-filled hole Zim floats in, “Here’s your junk food.”

He pulls the sticky donut from his pocket and tosses it to the siren, who snags it out of the air with his claws and stuffs it in his mouth. As he chews on the pastry loudly, his red eyes fixate on Dib.

His fins twitch with amusement. “Zim noticed how the Dib-feets longs for the ocean—”

“I don’t _long_ for the ocean—”

“Shush your smelly human mouth! Zim knows things!” Zim hisses, his tail slapping the water’s surface, “But as we discussed last night, Zim is willing to teach the Dib how to swim! Be grateful!”

Dib’s jaw drops. He stares at Zim in shocked amazement for a few moments before stammering, “Y-you…oh _shit_ , you really meant that? You weren’t just saying random shit to convince me to come here?”

Zim horks down the last chunk of donut and yells, “That is what I said! Now take off your pitiful foot-bindings and come here!” 

Dib doesn’t have to be told twice. Grinning from ear to ear, Dib kicks off his flip-flops, shucks off his hoodie, and tosses his shirt on top of it. As the boy approaches the edge of the deep pool, Zim glances at Dib’s chest curiously. 

“What beast gave you those scars?”

“What-oh.” Dib glances down at the two curved scars on his chest. “Nothing. They’re just scars from a surgery I had.”

As Dib sits down on the edge of the pool, dipping his feet into the chilly water, Zim hums thoughtfully. “This “sir-dree,” what was it for?”

Dib’s skin prickles and he frowns. Thankfully, Zim seems to pick up on his discomfort and backpedals. “If the Dib does not want to answer, he doesn’t have to. But! Zim thinks all scars are something to be proud of! Stop scowling, Dib-feets!”

In spite of himself, Dib laughs. 

_Maybe Zim isn’t as much of an idiot as I thought._

“Thanks, Zim. That means a lot—”

“Enough chatter!” Zim interrupts while holding his scaly arms out in Dib’s direction, “We have much to do!”

Dib blinks a few times in surprise, but smiles awkwardly and reaches out to shakily grab Zim’s webbed hands.

“Okay, okay, whatever.” He sighs, but he can’t stop the way his small smile grows ever wider.

* * *

The moment Dib takes Zim’s hands, the siren finds himself intrigued by the warmth that radiates through the Dib’s skin. He doesn’t let his curiosity show on his face, but he does make a mental note to study the Dib in the future. 

Humans are warm-blooded, where sirens are cold-blooded. 

Dragging himself back to the present, Zim forces himself to focus on the Dib. Carefully, he backs away from the edge of the deep pool and pulls Dib with him. And to Zim’s surprise, the human boy doesn’t struggle. Instead, he practically throws himself into the water. 

The moment he does, though, reality seems to set in and his brown eyes fly wide open in alarm. His dull nails dig into Zim’s bony hands, making the siren hiss, but he curls his tail in front of himself so the Dib has something beneath him. 

Zim picks up on the human’s heart beginning to race and snaps at him. “I will not drop you, Dib-feets! Stop your worrying!”

“Y-yeah, okay.”

Despite his words, Dib’s pulse still thrums in his veins and his breath stutters. Zim almost wants to scold the human boy again, but decides against it when he takes in the Dib’s demeanour. 

His eyes are wide, yet they sparkle with excitement. His breaths stutter, but they jump with anticipation rather than fear. Zim’s lips twitch, threatening to curve into a smile.

_The Dib-feets is ecstatic._

Ignoring the urge to tease his human companion, Zim begins instructing him. 

“Zim knows little about “legs” but you should try moving them like…like…” he trails off, trying to find the words before holding up one hand and wiggling his fingers back and forth, “Like the thing. The…two-blades thing, for cutting.”

“Scissors?”

“Yes! Move your weird leggy-appendages like the scissors-blades!”

Dib snickers. “Okay, whatever you say.”

After a moment’s hesitation, Dib takes a breath and begins kicking his legs like Zim instructed. His death-grip on Zim’s hands relaxes ever so slightly, which Zim considers a small victory, and the siren gently lets go of Dib’s hands. Instinctually, the boy uses his arms to paddle as well. Now treading water, Dib laughs in exhilaration.

“O-oh my God, I’m doing it. I’m swimming, I’m not sinking!” He babbles excitedly as he glances down at his feet beneath the saltwater. 

Zim snorts. “I’d hardly call that proper swimming, but yes. You’re doing...satisfactory.”

“Never thought I’d hear that come from _you_ of all people.” Dib laughs.

With a mock frown, Zim threatens, “If you’d prefer, I can go back to doing proper siren things and eat your gargantuan head.”

“No way, man!” the human boy replies with a broad grin, “You’re way more fun to be around when you’re like this.”

At his words, Zim stiffens. His ruby eyes fly wide open and his lips part just a bit as he processes what Dib just said. 

_I’m...fun…?_

Zim feels his face tingle.

_Nobody’s ever said something kind like that to me._

“Hey, Zim? What’s up with your face?”

Zim yanks himself back to reality. “Eh?”

Dib stops paddling with one hand to gesture at his own face. “Your face. It’s all lit up like a Christmas tree.”

“What is this “Crimmus tree” you spea-wait, Zim’s face is lit up?”

Dib nods. “Uh, yeah.”

With a pang of horrified embarrassment, Zim looks down at his reflection in the rippling water’s surface. And to his mortification, his cheeks are lit up with a soft green light. He slaps his webbed hands over his face and scowls at Dib. 

“You will not speak of this or I will feed you to the sharks.”

“You wouldn’t _dare.”_

“Try me.”

The two of them meet eyes for a few seconds…until the silence is broken by Dib splashing Zim in the face. 

Of course, Zim isn’t particularly bothered by this, but he’s not one to back down from a challenge such as this. He grins maliciously at Dib at the same time he sucks in water from his gills. “Oh, you little _urchin—_ ”

“Whatcha gonna do about it, fish-boy?”

Zim forces the water from his gills out his mouth in a powerful stream. Dib lets out an unflattering squawk as the jet of water smacks him square in the face, and Zim momentarily feels anxious when Dib coughs. 

But Dib is well enough after that to grab onto the edge of the pool and kick water viciously at Zim, so the siren figures the boy can take a lot more than a pressurized jet of water to the face. He uses his massive tail to absolutely _drench_ Dib with a wall of water. 

Their mock-fight continues for an indeterminate amount of time, but by the time Zim thinks to check the time, the sun has sunk below the horizon and millions of stars illuminate the clear night sky. Zim’s bioluminescent spots have begun glowing, reflecting in the water and sending beams of light dancing across the Dib’s freckled face. 

At the sight of Dib’s light-painted face, Zim momentarily pauses. He’s unsure why he does, but his hesitation gives Dib enough time to send more ocean spray cascading over Zim’s head and shoulders. Zim shakes his head, sending water droplets flying, and darts towards Dib with an impish grin. 

Webbed hands pin Dib’s wrists to the edge of the rocky pool and the human’s nose nearly brushes Zim’s face. The Dib laughs in a voice like the sun itself, and the warmth of his breath on Zim’s cheeks makes Zim’s heart thrum in his chest. Something in the siren is _drawn_ to the human, and he’s not sure why.

It’s almost frightening.

Zim’s eyes drift down to settle on the bracelet around Dib’s wrist. They narrow in anger and Dib sighs, gently pulling his hand from Zim’s grip to scowl at the device as well. 

“Shit. I totally forgot about this thing,” Dib mutters bitterly, “Dad’s gonna flip his lid.”

“Do human parents eat their own young as sirens sometimes do? If so, perhaps it is better that you do not return home,” Zim suggests, which draws another one of those warm, bubbly laughs from the human.

“No, they don’t. But I should get home before Dad considers it.”

Dib turns and hauls himself out of the water, and Zim can’t help feeling disappointed. 

If possible, he would’ve liked to talk with the Dib on the rocky beach until the sun rose once more. But the Dib’s life is much different from the life of a siren, and Zim supposes he’ll have to deal with that. He folds his arms on the flat rock Dib climbed out on, resting his head on them with a huff. “The Dib can’t stay longer?”

Dib slips on his foot-bindings with a morose shake of his head. “Unfortunately, no. I’ve already stayed too long as it is,” he turns to give Zim a small smile, “but if you’re not doing anything, and if I can get out of the house, wanna meet up here again tomorrow?”

Zim’s fins perk up as his excitement spikes. “Zim will see you here tomorrow at the same time?”

“Sounds like a plan,” Dib confirms as he pulls his shirt and sweater on once more.

The two of them say their goodbyes, then Zim watches silently as Dib jogs away through the saltgrass marshes between the beach and his dwelling. Zim stays there, swimming in lazy circles around the flooded cave, until the full moon is high overhead and the siren feels his eyelids growing heavy.

He’s just about to leave when he catches sight of flashing bioluminescence underneath him. With narrowed eyes, Zim dives down. He hisses in exasperation when he comes face to face with another siren from the Irken pod. 

“Skoodge.”

“Were you playing with a human just now, Zim?” the chubbier siren blurts out without warning.

Zim recoils, baring his fangs in warning. “Zim fraternizes with no _humans.”_

“I saw you, though,” Skoodge presses, spots flickering with amusement as he smiles knowingly, “and I saw the human. And you guys were play-fighting like careless seal pups. That seems a lot like “fraternizing” to me.”

Zim’s face does that strange tingly thing again. Skoodge barks out a victorious laugh. “Your face is doing the thing!”

“What _thing,_ Skoodge?”

“You know, the _thing!_ ” Skoodge gesticulates vaguely, “The thing that lovey-dovey sirens do a lot when they spend time with a possible mate!”

With a snarl, Zim swipes a clawed hand at Skoodge. The other siren dodges with startling swiftness, swimming around to grin directly into Zim’s face. “You’re gonna court the human, right? That’s some strictly forbidden stuff, you know.”

“I _know_ that! Zim is no idiot! The human and I are mere acquaintances!”

“Whatever you say,” Skoodge says in an infuriating tone, “but at least tell me more about this human!”

Zim smacks Skoodge in the face with his tail fins before darting deeper into the flooded caves beneath the beach. He’s vaguely aware of the smaller siren following him, but he grits his teeth and growls inwardly. 

_I do not intend on courting the human,_ Zim thinks, _I am merely using him._

* * *

Dib’s almost certain he’s going to come face to face with his father the moment he slides open his window and quietly slinks back into the house. Thankfully, when he flips on the light, no disappointed, goggle-clad scowl burns holes in his head. Dib heaves a relieved sigh.

For now, his inevitable yelling match with Professor Membrane is delayed another night.

Dib considers closing the window again, but decides against it—he feels a little less like climbing the walls when he can hear and smell the ocean, and if he can act at least somewhat “normal,” then he won’t have to worry about his dad’s ever-present disappointment. 

Unfortunately, just as he’s shucking off his sandy clothes, his cell phone vibrates from where he’d left it on his desk. Dib knows who it is before he even looks.

_Here we go…_

Dib takes a breath, picks up the call, then speaks in an overly-cheery voice, “Hey, dad! How’s your work conference goi—”

“You know you’re not allowed at the beach without supervision, Dib.”

Dib frowns. With a sigh, he cards his fingers through his wet hair and replies, “Look, I just went to meet a friend and collect shells. We waded into the ocean a bit, but that’s about it—”

“You deliberately disobeyed me,” Membrane says bluntly, and Dib winces, “We’ll be discussing this when I come home tomorrow night.”

“Dad, really, it wasn’t a big deal! I’m 15, I’m not a kid anymore!”

“Good night, Dib.” The call ends with a click.

For a few moments, Dib stares at his phone in surprise. Then, with a frustrated shout, he throws it at his bed, where it bounces off and clatters to the floor. The teenager groans angrily, tugs at his hair, and sits heavily down on the edge of his bed. 

As his mind starts racing with all the bad things that could come from his “chat” with the Professor tomorrow, his knee starts to bounce up and down anxiously. He scrunches his eyes shut.

_I shouldn’t have gone to the beach without finding a way to take off the bracelet._

A knock at the door drags him out of his dark thoughts. 

Without waiting for an invite, the door opens and Gaz steps in with a frown. “I heard you leave out the window. Dad’s probably pissed, huh?”

“How did you know I left?”

Gaz wrinkles her nose. “You’re about as graceful as a cow on stilts, Dib, it wasn’t hard to hear you clunking around outside.”

“Oh. Sorry.” Dib sighs halfheartedly. 

Gaz doesn’t say anything for a while, but after a minute or two has passed, she crosses the bedroom to sit on the bed beside Dib. She screws up her mouth. 

“You’re gonna go back to the beach anyways, right?”

Dib groans. “I’m that obvious?”

“Let’s just say that “subtle” is the last word I’d use to describe you,” his sister snorts, “but since you’re so desperate to go and drown, I guess I can cover for you tomorrow.”

“You’d do that? Really?” Dib exclaims, and Gaz holds up a hand in front of his face.

With narrowed eyes, she continues, “On one condition: you give me money for the arcade tomorrow.”

“Done. But what are we gonna do about the brace—”

Gaz reaches over to tap the surface of the bracelet in a swift, deliberate pattern. The device beeps and falls open. Dib gawks for a second.

“Are you fucking serious? It was _that_ easy?” he wheezes, finally.

Gaz shrugs, pulling the bracelet away from Dib and attaching it to her own wrist. “Dad gave me the code. Apparently he decided to trust me.” She shoots a cocky smirk at Dib. “A horrible decision, really.”

“I don’t feel particularly comforted when you say that while looking at me.”

“Oh, stop being a wuss, Dib, I’m actually being nice to you here.”

Dib frowns. “You’re hoping I drown, aren’t you?”

“Not really, but it would be pretty funny if you came back with an urchin stuck to you.”

“Sure. I’ll keep that in mind.” Dib sighs as Gaz starts to leave. “Hey uh, Gaz?”

She turns her head to look at Dib with one eyebrow cocked. Dib takes a breath. “Thanks. This means a lot to me. I mean it.”

“Whatever,” she says dismissively with a wave of her hand before making her exit.

Dib smiles. 

Perhaps the following day won’t be _all_ bad.

* * *

“A hulking _sunfish_ swims with more grace than you, Dib-feets.” 

“Oh, _thanks_ for the encouragement, fish-face.” 

The following late afternoon, Dib and Zim had met up again. And Zim can’t deny that he feels relieved. After what the Dib had said about his father being overbearing and terribly controlling, Zim was quite worried that the Dib would never be able to come to the beach again. 

So he’s quite happy to see his frie— _acquaintance_ again. 

Currently, Zim floats at the opposite end of the wide tide pool from Dib, who ungracefully swims towards the siren. He squints while he moves, having left his glasses with his shirt and shoes, but seems to be able to see where Zim is. So the fact that Dib is slightly visually impaired isn’t too much of a worry.

Finally, Dib makes it across the still water and grabs Zim’s shoulders for support. His breath comes in shaky gasps, but the sound isn’t in distress. With a smirk, he snickers, “Do you need a break, Dib-thing? You seem _tired.”_

Dib gives him an offended look. “Wha-no! I just don’t do much athletic stuff so I’m not used to swimming!”

“Does that mean you need a nap to replenish your stamina?” Zim presses. 

Dib flicks him in the chin. “No way. You’re not getting out of teaching me how to swim.”

“Curses,” Zim jokes, which earns him a playful kick in the tail from Dib. 

Dib lets go of Zim to hold onto the rocky edge of the tide pool. Zim crosses the water to wait at the opposite side again. They repeat this back-and-forth until Dib’s frantic paddling becomes more confident and less frenzied. He finds a rhythm in each stroke of his arms and legs through the water, and by the time the sky starts turning pink and gold, the pair float leisurely side-by-side at the edge of the pool. 

As Dib floats on his back, eyes fixated on the sky, he says, “Hey, Zim? Can I ask you something?”

“You just did.”

Dib snickers. “No, I mean—” he takes a breath, “—okay, I’ve been having weird thoughts lately.”

Zim makes a disgusted face. “If this pertains to your silly human “birds and bees” thing, Zim is leaving.”

“Ew, no!” Dib gags, “Not _weird-_ weird, just…things I can’t really explain.”

“Fine. Tell me your silly human thoughts, Dib-feets.”

Dib turns over, hopping up to sit on the edge of the pool with his feet dipping into the water. He slowly moves them back and forth, watching the water displaced as he does so. Finally, Dib murmurs, “Have you ever felt like…like you’re in the wrong place? Like you don’t belong somewhere?”

“...yes,” Zim replies hesitantly, “Zim has felt this before.”

“Well, ever since I first started harassing you when we were 12, I’ve felt less and less at home on land. I…I don’t know _why,_ but when I’m not near the ocean, I get this…” his hand shifts as though he wants to clutch at his heart, “...this _ache._ And since that incident a year ago-”

Zim snarls viciously. “I do _not_ want to speak of that incident, Dib-stink _.”_

Despite the tangible threat Zim sends him, Dib continues speaking as though nothing happened, “-it’s just gotten worse. Like, it almost physically hurts.”

Zim’s lips relax to hide his fangs as his ruby eyes drift down to fixate on the way Dib’s fingers twitch over his chest. As he does, Dib continues in a small voice, “D-do you know what that could be about? Or am I just going insane?”

“I’m not sure, Dib-feets.”

With a disappointed sigh, Dib places his hands on the rocky ground behind him and tilts his head back to look at the sky. “Well, thanks anyways. I, uh…I guess I should get going before Dad gets home.”

As Dib rises to his feet and shakes water from his hair, ZIm blurts out, “Will Zim see you again?”

The human boy freezes. Zim chews his lip. 

After an indeterminate amount of time, Dib pulls his shirt on and replaces his glasses on his face. “I…don’t know, Zim. I’ll try coming by, but I don’t know when that’ll happen.”

“Then Zim will wait for you, stink-beast.”

“That’s nice and all, but you might be waiting here forever—”

“Zim will wait.”

Dib turns to meet Zim’s eyes, and it’s then that his keen eyes pick up on the way the Dib’s face turns pinkish-red. His antennae perk up in interest. “I did not know humans could change their skin colour.”

“W-we can’t…?” Dib stammers as he hurriedly turns his face away.

For a time, Zim finds himself confused. Then, out of nowhere, his mind reminds him of what Skoodge had said the previous night.

_Your face is doing the thing! You know, the thing lovey-dovey sirens do a lot when they spend time with a possible mate!_

The young siren’s jaw drops. 

“Dib-beast, is your face red because—”

“ _Oh,_ would you look at the _time!”_ Dib interrupts loudly, glancing at his bare wrist.

Zim narrows his eyes. There’s nothing for Dib to look at on his wrist.

With an awkward grin, Dib waves at Zim and calls, “I-I guess I’ll see you around, Zim! Good night!” before making a very rushed exit from the beach.

Stunned by his new revelation, Zim just stares off across the rocky beach for a time. 

He’s not sure what to think of this, but perhaps he can glean some answers from his fellow sirens.

* * *

Professor Membrane arrives home at the same time Dib departed out the window that day. 

The teenager, caught up in his thoughts and deafened by the clanking of the gutter he shimmies down, is completely unaware of the professor parking in the driveway. And as Dib pelts away across the saltgrass hills, Professor Membrane approaches the back window and watches. He cocks an eyebrow in confusion. A quick glance down at his own Membracelet tells him that Dib’s bracelet is currently at the town’s local arcade, as Gaz had told him on the phone.

Yet the professor is watching his son race towards the sea.

His heart sinks, his blood running cold. 

_I cannot lose him too._

The professor shucks off his white lab coat, pulls his boots back on, and bursts out the back door after Dib. 

Membrane would likely be able to catch up with ease if he were to use his cybernetic enhancements, but the noise would also alert Dib to his presence. So, the professor remains on the ground and follows the path of flattened grass that Dib left behind.

When finally he reaches the beach, he follows Dib’s footprints through the mud and damp sand to a rocky, seldom-traveled part of the beach. Here, the trail gets hard to follow. The rocks are smoothed by the tides rising and falling, and no mud patches mar the ground, so no footprints are visible. 

Dismayed, Professor Membrane wanders through the wet spires of rock and algae-coated boulders at random. He does this for almost an hour, but something makes him pause. He strains his ears.

 _There!_ Over the roaring of the waves crashing into the coves and rocks, he hears something like voices. The professor lowers himself into a half-crouch and follows the disjointed voices echoing off the rocks. 

Before long, he comes across a massive dead tree, stripped of its bark by the sea currents and lodged between two rocky spires. On it, he notices several smeared damp spots that look suspiciously like the fingers of a waterlogged human climbing over the log. Carefully, the professor climbs atop the log to peer into a cove surrounded by six-foot walls of rock. 

In the centre of the cove is a flooded cave mouth about fifteen feet in diameter. And in that body of water, Dib is gently held above the surface by a creature Membrane has never seen in all his years of study, marine or otherwise. 

A siren.

It’s a stunning specimen, one with deep green scales like summer leaves, delicate webbed hands, and striking pink accents on its fins and antennae. In a frenzy, the professor yanks a small notebook and pencil from his pants pocket and wastes no time in making a rough sketch of the creature. And once that’s done, he takes notes on its behavior and characteristics.

  * _Contrary to legend, it does not hypnotize with its voice_


  *     * does it abstain by choice? is it attached to my son?


  * Moves gracefully, similar to dolphins or small-med sized sharks


  * Speaks in human dialect


  *     * garbled, clicking tone, yet clear to understand


  * Antennae


  *     * for detecting sounds, scents, perhaps? Maybe deep-sea navigation?


  * At least 2 rows of jagged teeth


  *     * carnivorous, predatory 


  *     * lose teeth like sharks??



The more the professor writes, the more he wants to learn. He _yearns_ for answers, for the opportunity to study everything about the creature. From its exterior, to its morals, to its language, to its internal organ function and structure…he wants to know it all!

He lowers his book to cast a glance at his son and the creature once more. This time, however, he stiffens.

_It is teaching Dib how to swim._

His mind wanders back to a similar situation, many years prior: a much younger professor Membrane, a cove shielded from prying eyes, a legendary sea creature teaching a human to swim. The professor’s stomach twists sickeningly.

_I must prevent another tragedy._

With a furrowed brow, Membrane turns, slides off the log, and starts for home. If he is to proceed with his studies and with the prevention of a second tragedy to the Membrane household, he’ll need to trust his son. He’ll have to leave Dib with his little green friend.

 _He must remain oblivious,_ Membrane thinks darkly, _If I am to prevent my son from being lost, then I must make some sacrifices._

_It is for his own good._

* * *

When Dib arrives home, Gaz tells him that their father has already gone to bed. 

She’s honest, and that’s what makes this peculiar—it’s no later than 8 pm, and their father never goes to sleep before midnight, no matter how tired he may be. He always brushed off his children’s worried inquiries with something along the lines of “why would I sleep when there is science to be done?” 

So Dib, not being the type to leave well enough alone, decides to go check his father’s room to see for himself. 

He’s quiet going up the stairs, walking on the balls of his feet and avoiding the parts of the stairs that creak, and doesn’t dare touch the handrail. He’s used that handrail enough to know that the screws holding it into the wall like to wiggle loose every couple months. Once he’s reached the top of the stairs, he tiptoes past his room and Gaz’s room to halt in front of the plain white door to his father’s bedroom. 

Dib takes a silent breath, reaches out, and opens the door.

The moment the light from the hallway spills into the room, Dib knows that his father lied to Gaz. The bed is neatly made, and the professor is nowhere to be seen. Dib steps through the door. 

He rarely enters this room, since his father gets angry whenever he or Gaz enter it uninvited. Dib never had the nerve to sneak in while the professor is gone out of habit, but something strange is going on and Dib wants to know why his father lied.

_He never lies._

The room has very few places to hide things, but Dib trusts his instincts and goes with the most likely places _he’d_ pick to hide things from his father. He rummages quietly around for a few minutes before he thinks to check the closet. 

He skirts around the bed on silent feet like a cat, stopping in front of the plain-looking closet doors. 

When he opens them, they creak just loudly enough to put Dib on edge, and he freezes several times to listen for the professor’s footsteps. Thankfully, he hears nothing. He heaves a relieved sigh and turns to look into the closet.

Dib’s breath catches in his throat.

Inside the walk-in closet, only slightly obscured by the white lab coats hanging from racks, are what looks like _hundreds_ of journals. Dib tentatively steps in and leans forward to read the messy handwriting on the spines of the journals.

_Mermaids Vol. 20. Sirens Vol. 2. Kelpies Vol. 7. The Loch Ness Beast Vol. 11._

Dib feels like someone knocked the air from his lungs. 

_My dad studied the paranormal?_

He turns to glance at the oldest-looking bookshelf and widens his eyes. He reaches out to brush his fingers over the spines of the dusty books. As he does this, his eyes drift down to the very last volume.

_Selkies, Vol. 143._

Dib cocks an eyebrow. 

_What’s a Selkie? And why did he write 143 volumes on them?_

At that moment, Dib hears his father’s heavy steps from the lab above. 

With a jolt of panic, Dib snatches the first volume and tucks it under his arm. He flicks off the light, hurriedly shuts the closet door, and tears out of the bedroom like he’s being chased by the devil himself. He’s careful to shut the door behind him, then bolts across the hall to his own bedroom. 

He shuts the door just as his father enters the hallway, and Dib scarcely has time to slide the journal under his bed before the professor knocks at the door. Dib readjusts his crooked glasses, straightens up his rumpled t-shirt, and stands upright with an impressively casual-sounding, “Come in!”

Dib only remembers he’s in trouble for going to the beach when his father steps in and shuts the door behind him.

The boy’s face falls. “I’m gonna get more restrictions put on me now, right?”

The professor blinks in surprise. Then, he heaves a sigh and runs a gloved hand through his hair. “Actually, son…I wanted to talk to you about something.”

“Uhh, okay?”

_This can’t be good._

For a few moments, the professor seems to be having trouble finding his words. This is another odd thing, since Dib’s father never seems to be at a loss for them. Dib manages to keep his concern from his face.

“Perhaps I’ve been…too harsh on you,” his father begins slowly, “ever since your mother was lost at sea, I have been frightened that I’d lose you and your sister. You do understand where my restrictions have been coming from, right?”

Dib raises an eyebrow in confusion. “Yeah, I knew that already. But we aren’t _her_. I don’t want to go on a boat or anything, I just like being on the shore and swimming in the shallows.”

“And that is something I understand now. So I am loosening your restrictions.”

“Wait, _what?!”_ Dib squeaks.

The professor nods. “You are three years from being an adult, and I suppose I’ve had difficulty coming to terms with that. You may visit the beach when you please, but be back before dark each night. I may have loosened your restrictions, but I expect you to be responsible with these new rules. Do I make myself clear?”

Dib nods, dumbfounded.

“Good. Now, I’m off to bed. For real this time.”

“O-okay. Night, dad.”

“Goodnight, son.”

The moment Membrane’s bedroom door clicks shut, Dib races to change into his pyjamas and practically _dives_ into bed. He casts one last glance at the bedroom door, then reaches under the bed to grab the journal he’d snatched from his father’s closet. 

It’s a leather-bound journal, one of the expensive ones the professor uses for his scientific endeavors, but unlike the plain black leather journals the man usually uses, this one is a worn-out brown. What stands out, though, is the intricately-carved design of a seal on the cover. Dib runs his thumb reverently over the design.

_I wonder why he doesn’t keep more cool-looking journals like this._

He opens the front cover.

* * *

**_December 2, 1990_ **

**_Upon my bi-weekly trek to the beach in which I check my offshore cameras, I came across a peculiar sight. I followed my usual route along the shore to the rocky portion of the beach, and was not expecting to encounter anything out of the ordinary. And yet I came across something simply extraordinary._ **

**_Rounding a spire of rock I used as a landmark, I came across the tragic sight of a seal ensnared in an old net. I could not simply leave the beast to suffer and waste away, so I quickly found a sharp stone and rushed to its side. I cut it free of the net, and before my very eyes, it changed form into a beautiful woman wrapped in a luxurious seal-fur soat._ **

**_She thanked me, and I, struck by her beauty and the mystery of her existence, offered to bring her to my home so I could treat her wounds and give her a hot meal. She accepted, and she now sleeps soundly on my sofa with bandaged wounds and sated hunger. The woman had no name that I could call her, so she and I talked well into the night about what she would like to be called._ **

**_The name she chose is Catherine, and she is a creature called a Selkie._ **

\- **_P. Membrane_**

* * *


	2. drowning

**Notes for the Chapter:**

> I'm so shocked and thrilled that so many of you love this fic! This is a ton of fun to write, and it's super validating to know that you guys appreciate it as much as I love creating it!

The days turn into weeks, and the weeks into a month, and Dib never misses a single day at the beach with Zim.

He has begun bringing his new swim trunks to school with him, so that he can race down to the shore as soon as the dismissal bell rings and meet his friend. His father hasn’t even raised a single question about Dib’s outings. Other than the occasional inquiry about how his day at the beach was, the professor has been oddly quiet in regards to Dib’s beach excursions. 

In addition to this, Dib has been slowly progressing through his father’s vast collection of Selkie journals, replacing one when he finishes it and snatching the next to be read. He even started taking the journals to his and Zim’s secret spot, where the two of them make up various theories on what could possibly happen next in the professor’s accounts.

Zim has even been showing interest in learning to read, so in exchange for teaching Dib to swim, the human had been teaching Zim how to read. 

“Okay, let’s go over these again…” Dib says as he steps into the cove with a smile.

He drops his backpack on a dry boulder, rummages through it, and brings out a set of laminated flashcards. Arms folded on the edge of the deep pool, Zim perks up. “Zim is ready for your flashing-cards.”

Dib doesn’t bother correcting the siren, instead approaching the edge of the water and sitting cross-legged on a flat stone. He shuffles the cards around before holding one up for Zim to see. Zim’s red eyes narrow as he squints at the card. 

“That says “the.””

“Yup,” Dib confirms, sliding the card to the bottom of the pile and holding up another.

“”Of.””

“Mmhm.”

They move through the whole pile of 50 cards, and Zim only makes a handful of mistakes. The siren is immensely proud of this when Dib tells him how many he got right and takes his success as permission to tease his human companion. “If only you could swim as well as the great Zim beats your flashing-cards.”

“If you wanna keep up the sass, I just won’t read the journal today.” 

Zim slaps his tail against the water indignantly. “If you do not bring out the journal, I will eat your huge head, Dib-feets.”

Dib rolls his eyes. As he tucks the cards back into his backpack and retrieves the journal they’re currently on, he sighs, “My head’s not  _ that _ big.”

“It rivals the head of a humpback whale.”

The human boy scowls at Zim. “Sometimes I wonder why we’re even friends.”

“Perhaps you enjoy being berated?”

“Uh, hell no,” Dib retorts, “What’s wrong with you?”

The siren lets out a chirping laugh, a sound that Dib reluctantly admits he’s begun to look forward to hearing. As his face heats up, he lowers it and hopes his messy fringe will obscure his blush enough for Zim to not notice it. With a cough to clear his throat, Dib flips open the dog-eared journal,  _ Selkies Vol. 63.  _ As soon as Zim notices the book falling open, his antennae twitch in anticipation and he stops laughing.

The siren folds his arms over the edge of the pool next to Dib, leaning over to look at the pages as Dib reads. Taking a breath, Dib begins reading the journal.

* * *

**_July 23, 1992_ **

**_I suppose by now that these journals have become less scientific and more personal, but I haven’t the faintest idea what else to call them. So for now, I will keep the running title of “_ ** **Selkies** **_.”_ **

**_As for how things have been going, Catherine and I still meet up rather often for tea and to exchange idle chatter. I must admit, I look forward to the days she returns from the sea to knock at my door. In fact, we meet so frequently that I’ve had a second key cut that I tuck under a gnome at the back door. She uses this key to enter the house if I’m not around, so it’s always a lovely surprise when I return home to see her already waiting for me._ **

**_On our most recent meet-up, she allowed me to study her coat. This was an incredible opportunity, and I was even allowed to wear it. Predictably, nothing happened, but it was still an incredible experience. The coat was incredibly soft and warm, and mottled in shades of grey. Yet it still didn’t feel like a normal coat. The moment I pulled it on, I could hear the sea and feel waves rushing over me. In my head, I heard gulls and dolphins and albatrosses, waves crashing against rocks and hurricane winds and the gurgle of water beneath driftwood. It was otherworldly and, dare I say,_ ** **magical.**

**_She brought up something odd when I returned her coat to her._ **

**_While folding it neatly in her lap, she brought up the topic of Selkie pups. I, being ever curious about her kind, was wholly invested in her story. She then proceeded to tell me how, when Selkie children are born, they are born wearing the coat of a Selkie. However, if those children are half-human, they may be born with physical deformities. She then proceeded to ask me what my thoughts were on this._ **

**_Of course, I’ve learned to suspend my disbelief when speaking about Selkies. So I accepted this whole “being born with coats” concept without doubt. She pressed on, asking how I’d feel if I were to have children and they had deformities. I answered honestly, saying that I’d have no issue if I were to have children and if they had deformities. She seemed pleased with my answer._ **

**_I’m not sure what her angle is with this line of questioning, but I feel like this is not the end of this topic._ **

**_-P. Membrane_ **

* * *

When Dib finishes reading, Zim hums thoughtfully. After a moment, he flashes a grin at Dib, “If the Dib-beast turns out to be a Selkie pup, that would be amusing.”

Despite his misgivings, Dib scrunches his nose. “I’m not the kid of a Selkie, Zim. I’m pretty sure I’d know if I were.”

“Hmm... Zim is unsure,” the siren says in a teasing tone, pressing a finger to his chin, “The Dib is quite oblivious to many things.”

“Oh, shut up.”

Zim cackles loudly. With a huff, Dib closes the journal and tucks it back into his bag before pulling off his t-shirt and tossing it on a dry boulder. His face splits into a grin and he stands up. Zim is still oblivious to Dib, holding his stomach and laughing, and the human boy backs up a ways from the water’s edge.

He pauses a moment. Then, he breaks into a dead sprint.

A few feet from the water, he leaps into the air. 

“Prepare to die, fish-boy!” Dib shouts, which alerts Zim.

The siren screeches and tries to get away as Dib cannonballs into the water with a colossal splash. Once Dib’s completely submerged, however, he makes no move to resurface.

The saltwater prevents him from opening his eyes, but he still revels in the feeling of the water pressing in on him from all sides. He lets out a bit of air in a slight sigh, uncurling his body to relax in the cool water. If he could, he’d stay here indefinitely. 

But unfortunately, he needs air.

He reluctantly starts paddling to the surface, where he breaks out of the water with a gasp. Dib shakes his head to rid his face of wetness and opens his eyes. Red eyes fixate him with a glare from less than a foot away. Dib flashes Zim a shit-eating grin.

“Gotcha.”

Zim spits water in his face. Dib splutters and flails.

From dry land, Dib’s phone chirps as his alarm goes off. Dib and Zim glance back at it, and with a sigh, Dib pulls himself out of the water and shuts it off. As Dib pulls a towel from his bag, Zim speaks in a small voice, “Zim wishes the Dib did not have to leave so early.”

Dib’s face heats up. In an attempt to hide it, he pulls his towel over his head and dries his hair with an awkward titter. “Why? You in love with me or something?”

The answer Dib gets is a jet of water spat in his face. 

Once he’s done drying himself off  _ again, _ Dib changes his sarcastic answer. “Sorry, sorry, that was uncalled for. I feel the same way about having to leave, trust me.”

Zim flicks his tail. “Do you still feel the ache in your chest when you leave, Dib-feets?”

“...yeah. Yeah, I do.”

To Dib’s surprise, Zim’s ruby eyes glitter with excitement and he bares his two rows of teeth in a broad smile. “Well, worry no longer, for the mighty Zim has brought you…” 

Zim ducks under the water with a splash and vanishes for a minute before returning with something clasped between his webbed hands. “...a gift!”

Dib approaches the edge of the water and kneels down, curiosity written in his expression. Zim reaches out and places a small, smooth item in Dib’s outstretched hands, and when the human looks at it, his eyes widen.

In his hands is what looks like an old glass bottle about the size of a pill vial, and inside the tiny bottle is an assortment of tiny, delicate shells. The vial is also filled with seawater, and despite sloshing around in the little space, the shells don’t budge. Dib turns it over in his hands gently, admiring the opalescent reflections of the setting sun on each shell. 

“O-Oh, my God. Zim, this is…I love it.”

“Hold it to your big, flappy ear.”

Dib wants to snap a rebuttal at Zim’s offhanded insult, but he refrains. Instead, he heaves an exasperated sigh and holds the vial to his ear. The moment he does, he hears the sea in all its glory. From birds to whales to waves, Dib hears it all crystal-clear. A soft exhale leaves him.

“Holy  _ shit.” _

Zim reaches up to gently tap the vial with one claw. “I know a siren who does enchantments, and I had him enchant this. Now, the Dib-feets can listen to this. It should stave off your longing-chest-ache-thing if you are unable to return to the sea for an extended period of time.”

Dib almost wants to cry. 

His father has never gotten him something as meaningful as this. Sure, Dib knows his father loves him, but the professor has rarely been around to celebrate his and Gaz’s birthdays, and sometimes even forgets them entirely. Being given something as thoughtful as this...it’s something Dib doesn’t think he’s ever experienced.

Zim’s eyes grow round and he cocks his head inquisitively. The siren pokes Dib’s cheek lightly. “Dib-feets? Is it...not to your liking?”

“Huh? No, I love it, I really do! Why do you ask?” Dib replies confusedly.

Zim’s antennae twitch. “Your eyes are leaking.”

_ Shit. _

Dib ducks his head and hurriedly wipes his face, which he only now realizes is wet with tears and not seawater. Despite his efforts, the tears continue to flow and Dib curses under his breath. 

“Sor-sorry, Zim, I-I don’t know what’s wrong with me,” Dib stammers, still furiously rubbing at his eyes.

As he does, a cold hand wraps around his forearm and gently pulls it from his face. Dib wants to yank away, but for reasons he can’t understand, he lets Zim guide his arm lower. The siren meets his eyes calmly. 

“Zim has studied human behavior when we are not meeting one another. This leaking-eyes feeling appears to be common. If it is so common, you shouldn’t consider it “wrong,” Dib-stink.”

“I-I  _ know, _ but it’s...it’s embarrassing,” Dib replies, “I shouldn’t be crying in front of you.”

“Why not?”

Dib opens his mouth to answer, but finds he doesn’t have a response. He hunts around for any line of reasoning that isn’t trivial, but he finds none. His mouth shuts. “I don’t know.”

Zim hums quietly, removing his hand from Dib’s arm. The siren lingers quietly for a few moments, then glances at the sky. “It is getting dark. You should be starting for home.”

“Oh. Yeah, you’re right.” Dib sniffles, wiping his face one last time before rising to his feet. 

He places Zim’s gift carefully in the pocket of his swim trunks, zips the pocket shut, and reaches down to pick up his shirt. Zim watches patiently as Dib gathers his things before chirping out a farewell. Dib returns it with a shaky smile, and the two head their separate ways. 

As Dib makes his way home, he comes to a realization.

Perhaps it’s just a placebo effect, or maybe it’s the gift from Zim, but Dib notices that the longing ache in his chest isn’t as bad as it was before. His fingers brush the outline of the tiny bottle in his pocket. As he does, a small smile flits across his face.

* * *

The third floor of the Membrane residence was constructed by the professor himself, and hosts an impressive laboratory. Safeguarded by state-of-the-art security systems also created by Professor Membrane, the lab’s inner chambers are virtually inaccessible by anyone who isn’t the professor. 

Thus, it is an excellent place for Membrane to construct devices in total secrecy. 

Dib and Gaz have never caught a glimpse of the innermost part of the lab, and the professor intends to keep it that way. He allows his children to use the unguarded outer laboratories for their school projects and the like, but they have never been allowed in further than that.

Despite the extreme levels of security, the professor finds himself anxiously glancing over his shoulder at the titanium doors every few minutes in the fear that somehow Dib will discover what he’s doing. Should his son figure it out, Professor Membrane can forget about carrying out his plan; Dib would most certainly run and warn the siren. 

The professor pauses.

_ Am I truly taking the best course of action? _

Before he can spiral into doubt, he shakes his head to clear it and goes back to the spiderweb-like device he’s been working on for the past month. 

_ If it is to ensure the safety of my family, it is certainly the best route to take. _

He tinkers with the device for a few more minutes, testing the bolts and links to ensure they won’t fail in action. When the professor is satisfied, he lifts the device and steps back from the counter to inspect it in its entirety. 

The device he’s created is a net, constructed entirely of aluminum and carbon fibre- lightweight enough to not be a hassle to set up, yet sturdy and flexible enough that a strong creature such as a siren will not be able to easily damage it. The professor nods approvingly. 

_ This will do nicely. _

He places the net down once again. As he does, a chill passes over his body, and he stiffens.

For a moment, he could swear he hears someone in the lab. The professor whirls around to face the intruder…but nobody is here.

He is alone. 

He could swear he catches the vague scent of saltwater.

A few heartbeats pass, “...Catherine?”

As expected, there’s no response. In spite of that, Membrane lets his gaze trail over the lab a few times before letting his hope run dry. He heaves a sigh.

_ Of course I wouldn’t get a response.Catherine has been dead for many years. Why would she be here? _

Yet, a small part of him still remains optimistic. The professor was an avid paranormal enthusiast in his younger days, and he’s encountered ghosts time and time again. It wouldn’t be a stretch to assume that Catherine’s ghost would come visit him. In fact, it would be quite in-character.

She was always fond of making mischief, especially when it came to the professor. Why wouldn’t her ghost come pull a few pranks on him here and there?

He’s caught off-guard when his net clanks loudly. 

Membrane turns his attention to his creation, and is thoroughly surprised to see it knocked off the counter, where it lies partially hanging into the nearby wastebasket. 

With a sharp inhale, Membrane reaches down to pick up the net. He carefully places it back on the counter. Having seen that, his mind races.

_ Is this a sign of some sort? _

_ Am I doing the wrong thing? _

_ Should I stop? _

After a few minutes in which the professor anguishes over whether or not to continue with his plan, he shakes his head rapidly. His brow furrows and he double-checks his net. He’s come this far, he will not turn back now. And for all he knows, he could’ve just put the net too close to the edge of the counter and caused it to fall. 

With a huff, he sets his sights on the goal ahead.

_ Catherine is gone. And I will not lose anyone else. _

* * *

“So how did he like your gift?” Skoodge asks when Zim bursts into his cave that evening, mind racing with excitement.

From behind a curtain of fan coral, Zim’s otter companion Gir screams, “Didja bring me tacos?!”

Zim has no clue what a taco is—probably some human food Gir scavenged from the surface at some point—so he ignores the otter’s question and focuses on Skoodge instead. Zim puffs out his chest with a grin and chirps, “He loved it so much he did the human eye-leaking-thing! Zim is  _ victorious!” _

_ Zim never loses! _

Skoodge cocks an eyebrow. “Victorious in...what, exactly?”

“Gift-giving!”

“Oh. Did he give you one back that wasn’t as good as the bottle I enchanted, or—”

Zim’s tail flicks and he shrugs his shoulders. “The Dib did not, but I have still defeated him!”

As Zim cackles loudly, a teasing smile spreads across Skoodge’s face. “So you  _ are _ taking him as a mate?”

At Skoodge’s words, Zim’s face begins to tingle, and he bares his fangs defensively. “I said nothing of the sort—”

“Whatsa’ mate?” Gir barks, but is once again ignored. 

“Whatever you say,” Skoodge sighs, sending bubbles rising to the roof of the cave, “but you must’ve had a reason to give him a gift in the first place.”

Zim opens his mouth, ready to rattle off a cocky explanation...but no answer comes to him. He chews the inside of his cheek in thought, then when that doesn’t help, he begins swimming back and forth in the cave with a hand pressed to his chin. Even then, his words fail him.

From the back of the cave, Skoodge chuckles. “So I am correct, then. You  _ do _ intend on courting the human.”

Zim hisses at him viciously, flaring his fins and flashing his bioluminescent spots in an impressive threat display. Skoodge, however, hardly reacts to Zim’s intimidation tactic and crosses his arms. “We were hatched from the same clutch, Zim, I know you quite well after 15 years.”

“Well, Zim knows  _ you _ just as well!” Zim snaps back, desperately hoping to find  _ some _ form of leverage that’ll make the other siren shut up.

Skoodge snorts. “You’re as perceptive as a human. That is to say, your perception skills are sorely lacking. You’re also just as bad at hiding your emotions.”

“I am  _ not—!” _

“You are bad at these things, and I am too slow and bad at hunting. This is why we were outcasted, you know this. But perhaps this gives us an advantage.”

_ What is he on about? _

“What  _ advantage _ does being cast out give us?” Zim snarls as Skoodge meets his gaze with calm eyes.

The chubbier siren quirks his lips in a smile. “Red and Purple likely won’t notice you courting the human. So, you and the Dib are unlikely to be found out and punished.”

At his words, Zim feels the angry fire in him die down. Something like relief and anticipation floods through his veins like an ocean current. As he replies to Skoodge, he can’t help the way his antennae perk up in excitement, “I suppose that is true.”

Skoodge hums in affirmation before crossing the cave to rummage underneath a pile of smooth stones. As he does, Zim’s mind starts to race.

_ I could court the Dib. Perhaps it would be nice to have a partner. _

_ Would he accept me as a partner?  _

_ How would it work, seeing as I dwell in the sea and he resides on land? _

“Best not to overthink it.” Skoodge calls over, which breaks Zim free of his thoughts.

“I don’t think at all!” Gir shrieks.

Zim scowls at Skoodge. “Zim is not overthinking.”

“Yes, you are,” Skoodge shoots back plainly as he chews on a fish he pulled from under the rock pile, “And I suggest you stop. If this human likes you as well—which he does, from what I can gather—then you should have very few problems. Just be yourself. That’s something you excel at.”

Zim struggles not to swell with pride at the compliment as he places his hands on his hips and shouts, “Of course I excel at it! I am  _ Zim, _ after all! Now if you’ll excuse me, I must procure another gift for the Dib!”

Skoodge starts to say something, but Zim rockets out of the cave before he can hear what his companion is saying. That isn’t helped by the fact that Gir tears out of the cave after Zim, shrieking with excitement the whole way. As Zim and Gir shoot through the clear waters with purpose, Zim can’t help the way his face splits in an excited grin.

He’s not sure whether or not he wants to form a mated pair with the Dib, but he certainly wants to partner with the human for life. And he’s going to be the greatest partner the Irken pod has ever  _ seen _ !

* * *

As the leaves turn from green to gold and the summer breeze starts to bite, Dib makes his way through his father’s journals and never misses a meeting with Zim. Due to the weather turning chilly, Dib stopped swimming for the year, but he still looks forward to their visits. 

By now, Dib has started reading the final journal. 

The journals have been full of twists and turns, each one intriguing enough to get Zim invested, and the two boys look forward to finding out what the final book hides beneath its cover. 

Today, however, Zim is nowhere to be seen. Dib calls for him several times and waits for an hour, but the siren makes no appearance. 

Dib can’t help but feel worried—his mind wanders back to the  _ incident— _ and waits until the sun starts to sink towards the horizon. Still, Zim is nowhere to be found. Dib heaves a sigh.

_ Guess I’ll come back tomorrow. _

He half-hopes that he’ll hear Zim chirp or whistle at him as he leaves, but as expected, Dib does not hear the siren at all. The wind whistles in from the open ocean, nipping at Dib’s cheeks and fingers, and he tucks his neck into his jacket with a shiver. He tucks his hands into his pockets and feels the shell vial against his cold fingers. A small smile finds its way to his face.

Somehow, the little vial has become a source of reassurance for Dib, a quiet and ever-present reminder that he  _ does _ have someone who cares about him fully. Because although he knows Gaz and the professor love him, they aren’t openly-compassionate people. Zim, however...Zim is someone who is unafraid of being himself, and of being open and honest with his feelings.

When Dib pushes open the back door, Gaz is playing videogames in the living room and the professor is clunking around in the lab upstairs. Nobody greets Dib, but this doesn’t bother him as much as it used to when he was a child. Instead, he kicks off his wet shoes, locks the door, and heads upstairs to his room. 

_ I guess if I’m not doing anything, I can finish reading this journal. _

* * *

**_October 13, 1995_ **

**_Catherine returned from hunting early today. She was successful, and brought home an impressively-sized salmon, which she cooked and surprised me with when I returned from work. Her cooking skills have grown exponentially since I first began teaching her, and she now rivals me in terms of skill in preparing food. I almost feel intimidated!_ **

**_She’s begun spending more time on land than in the sea, which both excites and disappoints me. I tell her often that she should keep in touch with her Selkie family, and not hesitate to return to the sea whenever she feels the slightest need to, but she’s become so infatuated with humans and our society that she’s begun attending classes at the local college and successfully secured a part-time job. And while I am thrilled that she is willfully choosing to spend more time here, I am worried that she may abandon her heritage._ **

**_It is a silly thing to be worried about, but I personally believe that you should not lose touch with your roots, and with where you came from. After all, without a connection to the past, how can we pave a future our ancestors would be proud of?_ **

**_I have rambled on too long. Catherine is calling me silly names, like “bookworm,” and “anemone-chaser.” I assume the latter is a Selkie insult meant to poke fun at the fact that I have not moved in several hours. A fascinating insult, certainly. I should use that on my coworkers. If nothing else, it should provide an amusing reaction._ **

**_-P. Membrane_ **

* * *

Dib tucks his bookmark into the pages and shuts the journal. He lies on his bed, staring at the ceiling with the book resting on his stomach for a few minutes. His fingers rub absently over the surface of his shell vial as he does, his thoughts calm and lazy like a winding creek.

His eyes start to slide shut, but before he can doze off, an offhanded thought captures his attention.

_ Dad’s never talked about our mom, has he? _

As long as Dib can remember, every single time he or Gaz has attempted to learn about their mother, the professor has deflected the question or changed the subject. Dib never really thought about it too much before, but now that he’s older, he realizes that these were all avoidance tactics. 

Surely if she were dead, he would’ve said it straight-up at some point. Yet, there are no family photos with her in them hanging on the walls or tucked into the photo albums. Dib narrows his eyes.

_ Something’s screwy here. _

After taking a moment to consider his options, Dib tucks the journal under his pillow and hops off his bed. He pulls on a clean sweater, then opens his door and makes his way down the hall towards the laboratory stairs. 

The cold metal of the steps make Dib’s feet ache as he climbs up them, but it’s nothing compared to the chill that’s slowly started to creep up his spine. He furrows his brow.

His father is hiding something. 

The outermost laboratory doors slide open as Dib approaches them, but as expected, the professor is hidden away in the inner sanctum. With an exasperated sigh, Dib crosses the sterile lab to the massive doors that separate the inner lab from the rest of the world. The moment he steps within five feet of the doors, an alarm chirps at him twice and a camera in the ceiling swivels to focus on him. 

Dib gives the camera a withering look. A moment later, the camera hides itself away in the ceiling panels again and the doors crack open just wide enough for the professor to squeeze through. The doors slam shut behind him, and the professor laces his hands behind his back.

“Ah, my boy-child! How was your day, son?”

Dib shrugs. “It was fine, but I’ve been thinking about something lately and was hoping you’d be able to talk about it.”

The professor places one of his gloved hands on Dib’s shoulder and ushers him over to the rickety wooden table in the middle of the lab. They sit down on equally-precarious wooden chairs at opposite sides of the square table, and linger in silence for a short time. Then, Dib rests his face on one hand and drums the fingers of his other hand against the table. “So, uh...I just wanted to know,” he takes a nervous breath, “what was mom like? I just...I don’t know, I’ve been thinking about a lot of stuff and wanted to know.”

For a long time, the professor doesn’t say a word. Dib’s half-convinced he severely messed up.

But after what seems like an eternity, the man heaves a sigh and runs a hand through his hair. “Your mother was…” he trails off before continuing,”...a kind person.”

Dib raises his head to stare at his father with rapt attention. 

“She was compassionate, hardworking, and free-spirited. She did what she pleased, when she pleased, much like you.” 

Dib’s face heats up. 

The professor chuckles and continues, “She was strong enough to lift me with ease, and Gaz is her spitting image. She had much longer hair, and didn’t squint so much, but other than that, Gaz looks almost exactly like her.” He nods in Dib’s direction, “Both you and Gaz have her eyes, though.”

That statement makes Dib’s mouth quirk up in a fleeting smile. He lowers his gaze to stare at a knot in the wooden table as he listens to his father wax poetic about his wife, and Dib finds it quite admirable.

The professor may not be the greatest parent, but Dib has no doubt in his mind that his father dearly loved his wife. 

When his father’s excited chatter about Dib’s mother begins to subside into calm recollections about tender moments they shared, Dib decides to take the plunge and attempt to slyly confirm some of his nagging suspicions.

When the professor pauses in his one-sided conversation, Dib clears his throat anxiously and starts drumming his fingers on the table again. 

“Was she a good cook?”

The professor nods. “When we first met, she was not. She once joked to me that she could probably burn water to a crisp.” Membrane chuckles. “But I taught her how to cook and she quickly surpassed me in terms of skill.”

“I guess that’s one thing you couldn’t beat someone at, huh?” Dib offers with a small smile.

“Indeed,” The professor hums in amusement.

Dib swallows.  _ Here goes nothing. _

“What was her name?”

And it’s as if a switch has been flipped. The professor’s open demeanour vanishes, and the sight makes Dib think of the steel doors to the inner laboratory slamming shut. Brow furrowed, the professor rises to his feet and flatly says, “That’s enough for now. I will discuss her more in the future, but right now…I’ve reached my limit, son.”

“O-oh, okay. Sorry,” Dib stammers, dropping his gaze to the floor quickly before mumbling out one last question.

“Why’d you tell me about her so easily after dodging it for so many years?”

Membrane halts on his way back to the inner lab. He heaves a heavy sigh and scratches at the back of his head.

“I’m not sure, myself.” He’s quiet for a moment. “But I suppose it has something to do with how much I’ve seen you grow. And…well, I personally think that a connection to the past is rather important. Everyone should maintain a connection to their past.”

_ Wait a minute. _

“After all, without a connection to the past, how can we pave a future our ancestors would be proud of?”

Dib’s blood turns to ice. 

The professor vanishes into the inner laboratory. 

Dib’s hands shake. 

_ Holy shit.  _

He rises to his feet and tries not to sprint from the lab. 

_ I need to go over that journal with Gaz. _

* * *

Only when the professor is certain Dib and Gaz are in bed does he leave the inner sanctum with his aluminum net tucked away under his lab coat. The man shuts down the lab lights, locks the doors behind him, then leaves into the night.

He follows Dib’s beaten-down trail from the house to the beach, then uses memory alone to navigate through the rocky beach to the hidden cove. It doesn’t take long—the professor has always had an excellent memory—and once he’s there, a quick check with a thermal camera confirms that the siren isn’t within viewing distance. 

_ Good. It will not know the net is here. _

Once that’s done, the professor gets to work rigging up the net in the deep pool the siren and Dib use to swim in. It’s chilly work and tedious as well, but within an hour, the professor has successfully set the trap and activated the cloaking panels on the net to hide it. 

He’s come this far, but his thoughts still nag at him, rattling around his skull like ping-pong balls.

_ Will I destroy my relationship with Dib? _

_ Will I accidentally injure the siren before I can release it in the open sea? _

_ What if the siren fights back? _

He swallows hard. 

_ I’ve come this far. I cannot back down now. _

He takes a deep breath and lets out a whistle that sails out over the turbulent whitecaps of the sea.

* * *

“Go  _ away, _ Dib. I’m  _ busy!” _

“Gaz, I swear it’s important! Like, world-shatteringly important!”

“You said that about the dead bat you found in the shed three years ago.”

“I swear this is  _ actually _ important!” 

Dib groans, pressing his forehead to Gaz’s bedroom door and sliding down to the floor where he slumps on his knees. He purses his lips. With a confidence he doesn’t feel, he raps his knuckles rapidly against his sister’s door. He doesn’t stop his frantic knocks until the sound of stomping feet reaches his ears. Then, he scarcely has time to scramble back into the hall before Gaz wrenches open the door and glares daggers at Dib.

_ “What,”  _ she hisses.

Without waiting for an invite, Dib clumsily hops to his feet and darts into Gaz’s room, where he slams the door shut behind him and locks it. Gaz mutters profanities under her breath. Dib ignores it. 

With the journal clutched to his chest, Dib whirls around to fixate Gaz with wide, bewildered eyes. Only now does the fire in her eyes begin to die down. She crosses her arms. “What’s with the stupid book?”

Dib paces back and forth, his heart thrumming wildly in his chest as he whispers, “I stole it from dad’s room.”

“You  _ what—?!” _

Dib holds up a hand in surrender. “L-look, I had a theory. And...and I’m certain I can figure it out tonight. I just need you to hear me out.”

Gaz scrutinizes him for a few moments, perplexed. Finally, she heaves a sigh and crosses her room to slump down in her gaming chair. “Fine. What’s your stupid theory.”

Dib stops pacing and nervously crosses Gaz’s room to sit on the edge of her bed. They face each other for a short time, then Dib holds out the journal and flips to where he left off. 

“This is one of 143 journals dad wrote in the 90s, all of them detailing a mythical creature he met and brought into his home,” Dib explains in a hushed tone, “her name was Catherine, and she was a Selkie. I think...I think she might be our mom.”

Gaz doesn’t answer. Dib is too nervous to steal a glance at her face. 

With a hum, she leans forward in her seat to look at the journal. “And you want me to be here with you so you know you’re not going crazy, yeah?”

“Th-that’s the plan…” Dib murmurs.

“Then read already. You’ve got me invested, somehow.”

Dib finally looks up. Gaz is staring at the journal with mild interest glittering in her brown eyes, and just the sight of that fills Dib with newfound confidence. A soft breath leaves him. 

“Okay.”

They scour the worn pages of the journal together, not speaking a single word. Each journal entry starts implying more and more things about the professor’s feelings for Catherine, and while Dib is almost certain he’s right at this point, he  _ needs _ confirmation.

He’s not sure how much time passes, but halfway through the book, they come across the entry they’d been searching for.

* * *

**_December 24, 1997_ **

**This is certain to be one of the happiest days of my life.**

**This evening, Catherine came to me with the brightest smile I’ve ever seen. I asked her what got her so excited, and she held out something in her hand. It was a pregnancy test, and it read positive.**

**I calmly asked her if this was what she wanted, and I would be alright with whatever she chose. She confirmed that she wanted to have the child. And that was when my emotions made me forget my dignity entirely.**

**Catherine said I cried, but I cannot recall. I only recall being so incredibly happy that I laughed aloud and lifted her into the air. We held each other and cried for a time before we decided to move to the kitchen and begin discussing things over a cup of tea. Money is no problem, what with my job and her bringing in extra cash through her own part-time job, so we mostly went over names.**

**She and I decided on two by the time the clock struck midnight.**

**If it is a boy, his name will be Dib. And if it is a girl, Gaz.**

**I cannot wait until the day I finally get to hold our child. The mere thought of it makes me tear up.**

**If one day our child finds this journal, I hope that they understand just how much joy they bring me. I plan to be present for our child as much as possible, to teach them the ways of the world, and to guide them gently as they decide what sort of person—or Selkie—they wish to be.**

**-P. Membrane**

* * *

Dib and Gaz stare blankly at the entry for a few minutes, both trying to process the bombshell they’d just unearthed. Dib’s mouth is dry and his fingers tremble as they hold the journal, while Gaz remains outwardly impassive. But Dib knows Gaz well enough to understand that she’s also reeling from this shocking discovery. 

When finally they raise their heads to meet each other’s eyes, they utter the same words at the same time:

“Holy  _ shit.” _

As Gaz slumps back in her chair to stare at the ceiling, Dib slaps the journal shut and leaps to his feet. It takes him no time at all to unlock Gaz’s bedroom door, and once that’s done, he yanks it open and bolts for the lab. 

_ Dad, I have a  _ lot _ of questions for you! _

When he arrives, however, even the outermost lab door is locked. WIth a frustrated growl, Dib starts banging on the door loudly. As he does, he shouts, “Dad! You’ve got some shit to answer for! Like,  _ really _ fucking important shit!”

He pauses for a moment to listen for a response, but hears nothing. Dib mutters a few curses under his breath and reaches into his pocket for his cellphone. He wastes no time in finding his father’s contact information and calling him. 

After the first ring, Dib recognizes the sound of his father’s ringtone from the master bedroom. With an eyebrow cocked in confusion, Dib ventures back down to the second floor and tentatively opens the professor’s bedroom door. 

There, on the bedside table, is the professor’s phone. Dib drags a hand down his face in irritation. 

_ The one time he doesn’t have his phone on him is when I need to talk to him. Great. _

The teenager’s about to turn and leave, ready for a night of sulking and existential crises, when he pauses. He glances back over his shoulder at his dad’s phone, then down at his own. His brow furrows. 

_ Shouldn’t he be able to answer my call with his Membracelet?  _

The gears in his head start to turn over, and Dib starts noticing things he brushed off before. 

The sudden freedom. The lies. The unusual amount of time locked in his inner lab. The refusal to tell his kids what he’s working on.

Dib’s phone falls from his fingers and bangs against the wooden floor. 

_ He knows about Zim. _

His heart rabbits wildly against his ribcage.

_ He built something to catch him.  _

Dib whirls around and sprints downstairs, where he bursts out into the chilly autumn night. His bare feet burn as the cold sea wind bites at them, but he only pushes himself faster, faster,  _ faster! _

He can’t let his father do something to Zim. If something were to happen to the siren, Dib’s not sure either of them would ever be able to fully recover. 

His mind supplies him with a quiet,  _ This is like what happened last year, _ and Dib tries to ignore it. 

The only thing he should focus on is saving Zim.

* * *

“Is you gonna give your friend a present?” Gir chirps excitedly as he and Zim swim for the cove. 

Zim flashes his companion a razor-sharp grin. “Yes, Gir! I have created an excellent gift for the Dib-smelly!”

His claws tighten almost protectively around the kelp-wrapped gift he carries with him. A smile plays at his lips. He  _ knows _ Dib will like what Zim made, and this time the gift is a creation entirely of Zim’s. None of Skoodge’s enchantments or Gir’s weirdly adhesive spit have touched the gift. 

As his fins vibrate with excitement, he picks up on a distant, high-pitched whistle. Zim’s antennae perk up in the direction of the noise as a happy trill rumbles in his throat. “The Dib waited for me.”

“He soun’s like a train!”

Zim turns to place a hand gently on Gir’s head, and the little otter sticks his tongue out goofily. With a soft laugh, Zim pats Gir gently and says, “Stay here while I briefly visit the Dib. Zim will return shortly!”

“I’m short!” Gir cackles. 

And with that, Zim darts towards the mouth of the cave he uses to access the cove. 

The mouth of the cave is partially obstructed by a tangle of kelp and dead coral, but it’s still open enough for a small siren like Zim to wriggle through. Once he squeezes through the narrow entrance, the cave widens to about twice the width of Zim’s arm span. From there, the cave twists and turns like an octopus’ arms, leading to dead ends and switchbacks that could easily lead one to get turned around, but Zim navigates the tunnels with ease. Guided by his keen sense of smell, brightly glowing spots, and crystal-clear vision in the dark, Zim has no trouble following the proper tunnel to the surface.

He’s just about to breach the surface when an odd feeling makes him stop.

There’s an unnatural scent here, one Zim certainly hasn’t noticed before. It reminds him of humans and their suffocating four-legged beasts they travel in, but there’s also a faint scent of ozone like the air before a storm. The siren shivers with anxiety and clicks inquisitively a few times to check if the Dib is here. 

Nobody responds. 

Zim is just turning to leave, spooked by the whole situation, when the water around him grows charged. The siren has felt this before; this is the feeling Zim gets before lightning strikes the sea. Clutching his gift to his chest, he pumps his tail in an attempt to bolt out of the small space, but he’s too slow.

Electricity explodes in the water, locking Zim in place as he opens his mouth in a soundless scream. As waves and waves of electricity lock his muscles in place, he catches on to the sound of flexing metal and clanking chain-links. Panic makes his heart pound, and he struggles to break free of the electrical charges that jolt through him. 

Something presses in on him, trapping him on all sides just before the electrical charge ceases. Zim struggles, whistling and hissing and flashing his bioluminescent spots as he tries his hardest to escape the aluminum net. Unfortunately, despite his best efforts, he’s dragged to the surface and out onto the rocky beach. Sharp pebbles cut into his tail and palms as he thrashes, but he keeps it up. 

If he can manage to scare off the human attacker, he can find a way to free himself. 

The net tightens, restricting his movement further. Zim lets out a long, low noise halfway between a hiss and a snarl. In response, the human trapping him comments, “Certainly an intimidating noise.”

The human steps into Zim’s line of sight, and the siren cowers back with a snarl. This person is no child, this is an adult in his prime with an imposing, stocky frame and a spotless white coat. The man kneels in front of Zim with a thoughtful hum. 

“I apologize for the treatment, my friend, but I have my reasons.”

And despite the impressive show of intimidation that Zim puts on, he’s absolutely  _ terrified. _

_ Not again. I promised myself it wouldn’t happen again. _

The man reaches out as though to touch Zim, and Zim snaps at him in self defense. 

_ Not again not again not again not again— _

His mind races back to the _incident_ he and the Dib silently agreed never to speak of again.  


* * *

_ It was a rainy day.  _

_ The waves slapped against the rocks, the wind howled, and gulls cried mournfully as they tried to ride the air currents.  _

_ On this day, Zim wandered too close to a tangle of human trash and found himself hopelessly ensnared in an old wire net. He struggled valiantly, but every thrash of his tail or twist of his arms made the thin wire cut into his flesh and stain the water red.  _

_ And as sharks started circling, Zim fled to a sandbar just off the shore of the rocky beach. He’s not sure how long he laid there, shuddering on the algae-coated sand, but long enough that the tide started coming back in and the sandbar started becoming submerged again. The encroaching sharks scared Zim out of his wits, and he started throwing rocks as best he could to try chasing them off. _

_ It was about this time that someone called out to him. _

_ “Hey, are you...stuck?” _

_ Zim whipped around with a loud hiss to see his greatest foe, the human Dib, standing on the rocky beach in rubber boots and his stupid black coat. Zim flared his fins with a snarl, knowing that the human could not possibly have good intentions.  _

_ After an intense staredown, the Dib broke eye contact and started collecting rocks from the shore. He did this until his pockets were full, then he waded into the shallows with his hands held out in a placating gesture. Zim was not convinced.  _

_ He managed to bite the Dib a few times, but aside from a few human curses and a flinch, the Dib scarcely reacted to the attacks at all. He just used his arsenal of sharp stones to frantically cut the wire net away from Zim.  _

_ Once the Dib had freed him, Zim spoke no words. He hardly even met the human’s eyes before giving one last vicious hiss and shooting back out into the open sea, sharks in pursuit.  _

_ Zim was humiliated. But at the same time, he’d felt something more from the Dib. Something  _ kinder _ than the hostile demeanor he wore while pursuing Zim.  _

_ Zim pushed it out of his head.  _

_ The Dib was just a stupid human. That was all. _

* * *

Zim would give  _ anything _ to see the Dib appear like he had in that situation. 

The man reaches out for the net and Zim darts forward to sink his teeth into the human’s forearm. To his surprise, when he does, pain shoots up his jaw and his teeth make a metallic clank against the man’s arm. He hisses again, shaking his head as he presses himself as far away from the human as he can.

“Ah, did that hurt? It must not have felt good, I apologize,” the man remarks, “You see, I have metal arms. You cannot hurt me, young man.”

Zim still doesn’t speak. This hulking land-dweller does not deserve words. 

Finally, the man notices the wrapped item in Zim’s claws. “Oh, is that for my son? I imagine it is. Unfortunately, you likely will not be able to give it to him. It’s rather a shame, but necessary—”

“What are you  _ doing?!” _

Zim and the man look back to see Dib scrambling over the dead log he uses to enter the cove. The boy’s chest heaves with labored breaths, his glasses are crooked on his face, and he wears no shoes. For a moment, Zim wants to speak but chooses not to. 

“Son, what are you doing here?” the man asks as he rises to his feet.

Dib tears his gaze away from Zim to glare daggers at his father. “What are  _ you _ doing here?”

“I am—”

“You kept  _ so many _ big secrets, like, life-changing secrets, from me and Gaz. You think you’re allowed to ruin the  _ one _ secret I kept from you?” Dib snaps, and Zim is surprised to see Dib’s father wince at the accusation. 

The man runs a hand through his hair. “This is different…”

“Is it? Is it  _ really?”  _ Dib says bluntly, lifting up the book in his hands. 

The professor pales. “Where did you get that?”

“When were you going to tell me and Gaz—”

“Dib,  _ enough.” _

“That we’re children of a Selkie?”


	3. when the storm is over

**Notes for the Chapter:**

> **TW FOR CHILD NEGLECT, MEMBRANE'S SHITTY PARENTING, AND ANIMAL DEATH**

**_12 years earlier_ **

_ Professor Membrane walks along the shore as a fine mist of seawater and rain showers down on himself and the baby girl sleeping in the sling across his chest. A tiny, warm hand wraps around his calloused fingers and the man can’t help but smile at the little boy holding his hand and skipping alongside him in a yellow raincoat.  _

_ Today is the day Catherine is supposed to return from the sea, from her excursion to visit her family. She visits them every few months, taking a few days off of work and school to don her coat and vanish into the surf.  _

_ She always surprises Membrane, so he decided he’d like to surprise her instead for once with their two lovely children at his side. _

_ He guides their son around rock spires and deep tidepools, approaching the sheltered cove where Catherine always resurfaced. He smiles warmly, excited to see her once more. _

_ As they draw closer, however, Membrane grows increasingly aware of the sound of fighting seagulls and raises his head to look at the large flock that dance and dive over the next rise. Being an ever-inquisitive scientist, Membrane supposes he should go check on the noise. After all, who knows? Perhaps the gulls are harassing some poor creature caught in a fishing line. _

_ He lifts little Dib over a large boulder before carefully climbing over it himself. They make their way along the shore with carefree curiosity. _

_ When Membrane crests the next rise, he squints with a hand over his eyes. _

_ The seagulls are swarming something at the water’s edge, and red stains the surging sea waves. The professor’s face falls.  _

Some poor creature must have been hurt.

_ Curiosity gets the best of him, and he lifts a tired Dib up onto his shoulders before slogging across the rocky beach towards the keening gulls. The birds don’t spook until the professor and his children get astonishingly close, but when they do, the professor wishes they’d just stayed. _

_ There on the sand and gravel lies a dead seal with glassy eyes and a partially-eaten corpse.  _

_ Its eyes are brown, and Professor Membrane would know those eyes anywhere. How could he forget them, after meeting them over cups of cheap coffee, after seeing them fill with love as he whispered sweet nothings to the smiling face those eyes belonged to.  _

_ The professor’s stomach lurches, and he gags as the smell and the revelation hit him.  _

_ The seal is a mottled grey with darker spots like freckles on its snout and long, dark lashes. Membrane staggers back with a choked noise.  _

_ “Catherine.” _

* * *

_ Months pass, and Membrane has decided to never speak of Catherine again.  _

_ Not to himself, not to his children, not to his family. She was classified as a missing person with Membrane himself as the prime suspect. Although the lack of evidence quickly proved Membrane to be not guilty, the mere idea that  _ he _ could be suspected as her kidnapper crushed him. _

_ He throws himself into his work these days. _

_ He gave up his studies of the paranormal and hid his journals away, along with the Selkie coat Dib was born with. Membrane has seen the way his three year old son gazes out the window at the sea with a wild, longing eye—the boy is a Selkie child through and through, and that scares the professor immensely. _

_ Every time he considers telling his son stories about Catherine and Selkies, Membrane only sees the rotting corpse of his wife’s alternate form. He presses a hand to his forehead, leaning forward over his desk with a world-weary sigh. No, he will not allow the same to happen to his son.  _

If only they both were born without coats, _ the professor thinks somberly. _

_ Only Dib was born with a Selkie coat; born with the ability to shift forms. But neither of Membrane’s children will ever be allowed to visit the seashore. No matter the cost, he will not lose another loved one to the unforgiving fangs of the sea. _

* * *

Dib’s body shakes as the adrenaline of both standing up to his father and the proximity of the sea pulses in his veins. The smell of the sea, the wail of seabirds, and the fearful chittering and hissing of Zim trapped in the metal net hit Dib all at once as soon as he’d clambered over the driftwood log, and it filled him with a sort of fury he’d never felt before.

Something in him is fixated on the inherent  _ wrongness _ of the professor’s presence and the net clanking against the rocky beach and an animalistic sense of protectiveness threatens to choke out his reason. Yet, he stays as collected as he can and holds up the journal as he steps icily towards his father. “Were you just gonna keep this from us? Let us live in ignorance and never learn about our mother?”

“I was,” Membrane replies bluntly, eyes narrowing behind his ever-present goggles, “but you’ve been snooping where you aren’t allowed, haven’t you?”

“Yeah, because you wouldn’t tell me anything,” Dib snaps.

“My goals were with your best interests at heart. I am  _ protecting  _ my family—”

“By killing my only fucking friend?!” Dib snarls viciously, nails digging into the journal’s leather binding.

The professor widens his eyes. “Kill-  _ no! _ I would never kill an intelligent living creature! I was going to study it, then release it elsewhere.”

Dib crosses his arms. “Study him, how?”

The professor averts his eyes. Dib hisses through his teeth. “You won’t kill him, but you’ll tear him apart and put him back together “for science.” Real reassuring.”

In the net, Zim chatters nervously. The professor turns his back on Dib to kneel beside the net. “You disobeyed me numerous times for your own selfish gain.”

“You’re calling  _ me _ selfish?!” Dib laughs incredulously. “ _ Shit, _ I’m never gonna get through to you.”

_ But was I actually being selfish?  _

Dib stiffens. 

_ Was I jeopardizing my dad’s hope to keep me safe just so I could visit the sea? So that I could learn about something mysterious? _

The boy’s eyes drift down to the round, terrified red eyes fixated on him through a screen of carbon and aluminum. 

_ I don’t know…but if I save Zim… _

Dib drops the journal on the rocks. 

_...then at least I can do  _ something _ that isn’t selfish. _

With a deep breath, Dib braces himself. He grits his teeth, clenches his fists...then he breaks into a dead run towards his father. 

Dib gives the professor no warning before he slams all his weight against his father’s back. Membrane lets out a surprised shout, trying to regain his balance and failing miserably as he falls sideways into the deep pool he’d plucked Zim from. Dib’s bare feet bleed from the rocks and shells underfoot, and he’s shivering in the chilly wind, but he doesn’t hesitate as he hurries to Zim’s side and starts trying to find the net’s opening. 

The professor resurfaces with a spluttering breath and swims for the water’s edge. Dib hisses curses under his breath. Zim chirps and hisses in fear. 

Dib’s fingers find the net’s opening. He yanks it open, pulling it away from over Zim’s head with a clank. For a moment, siren and boy meet each other’s eyes in silent understanding. 

Then, Zim slips into the water with a joyous whistle and vanishes. 

Dib rises to his feet, panting with exhilaration. 

A large, drenched hand grabs him by the forearm.

Dib turns his head to meet his father’s eyes. He shrinks back at the anger he sees there. 

“I’ve been far too lenient with you, it seems.” 

“...dad?”

The professor turns brusquely and drags Dib along carelessly with him. Anxiety begins to dig its merciless claws into Dib, and the boy brings his other hand up to claw at his father’s grip on him. As expected, this doesn’t help at all.

Metal hands aren’t gentle or forgiving.

* * *

Gaz watches out the window as her father drags Dib to the house. 

She can read people’s body language like a book—it’s just something she can pick up on like a sixth sense—and she’s seeing a novel laid in front of her in the shape of her father and brother. Dib is terrified, his eyes blown wide and his bloodied feet are skidding on the wet grass as the professor coldly stalks forward. The professor’s shoulders are set and his steps tell Gaz that he’s absolutely furious.

Gaz has never feared her father before, but she fears him now. 

Not for herself, but for Dib. She doesn’t know what he did, but she has a feeling it had something to do with the journal, and the discovery Dib made. She gnaws at the inside of her cheek nervously.

_ This isn’t gonna go well. _

The back door slams shut as the professor drags Dib inside, and Gaz flinches as the figurines on her shelf rattle. 

Then comes the shouting. Mostly from the siblings’ father. His voice is thunderous and menacing, and while he’s never laid a hand on either of his children before, Gaz’s heart thumps against her ribs. With a shaky breath, she pulls on her headphones and starts up her game at max volume. 

She’s never been able to work up the courage to help Dib, and she’s sickened with herself because of it. But hopefully, if she can drown out the shouting, then she can pretend all is well.

_ There’s no fight downstairs.  _

_ Dib is in his room drawing diagrams of cryptids.  _

_ Dad is in his lab. _

_ Everything is fine. _

* * *

A month has passed since the blowout between Dib and his father, and since then, the professor has made a number of changes to restrict his son even further. 

The windows and doors have fingerprint-enabled locks on them. Dib’s bedroom windows have been covered from the outside to prevent him from even looking at the sea. He takes classes online. 

And the only thing keeping Dib from losing his mind completely is the small vial of ocean water that Zim had gifted him. 

Dib never knew any of his Selkie traits were actually  _ presenting _ themselves until now. But now that he knows, he envies Gaz for not showing any Selkie traits. Where Gaz couldn’t care less about being cut off from the ocean, Dib feels like he’s dying. 

His mind runs in frantic loops, chasing itself around and around his cranium and knocking his brains loose with every pass. His skin itches as though it’s drying out, but it looks fine. He feels dehydrated and drinks more water than he’s ever had to drink. The ever-present ache in his chest has intensified into something akin to flu-like pain that’s infected his joints, his muscles, his entire  _ body, _ and even Advil isn’t helping. 

To combat the withdrawal-like symptoms he’s suffering, Dib’s taken to pacing, drawing, and writing. He’ll do  _ anything _ to keep his sanity from slipping away, even if those things don’t help much at all. 

The only thing that helps is Zim’s gift.

Dib lies curled on his side in bed, the cool vial’s surface pressed to his forehead as he just  _ revels  _ in the muted ocean sounds echoing in the vial. His eyes are closed, and for once his hands don’t shake and his skin doesn’t itch. He draws his knees further into his chest. 

_ I need to get out of here. _

Dib lets out a shuddering breath. 

“Dib?” 

Dib opens his eyes reluctantly, not wanting to leave his temporary bubble of sanity. But with a groan, he flatly replies, “What?”

The door opens and Gaz steps in, closing the door behind her. At the sight of Dib, she winces. “You look—”

“Yeah, I know, I look like shit. You can blame that one on dad,” Dib snaps shortly.

Gaz’s eyes flash with hurt, then frustration. She folds her arms across her chest. “Don’t talk to me like  _ I’m _ the problem here. I didn’t do this to you.”

Dib almost starts arguing with her, but catches himself and drags his hands down his face in exasperation. “I’m sorry. I-I know, I just...my brain isn’t working right anymore. I’m losing my mind.”

“I know. And it’s really bugging me to see you waste away slowly like some moldy sandwich—”

“Thanks.”

“—so I’m gonna do my best to help you out. Okay? I want to help you, Dib.” She crosses the room to sit next to him on the bed.

Dib stares at her for a few moments, then drops his gaze and focuses on his nails, which he’s chewed down to the nailbeds in anxiety. “How are you gonna help me? I mean, I appreciate it a lot, but I just...don’t know how to get out of this one.”

“I’m figuring that out,” she says, “but I want you to tell me what’s happening to you. I feel like it has something to do with you being more Selkie than me, but I don’t know the details. Do you?”

“No, I don’t,” Dib sighs, “Dad’s journals were mostly accounts of his experiences with Cath— _ mom _ , and there wasn’t a lot of actual Selkie information there. And I’m sure he must’ve moved the journals elsewhere now so I can’t find them again.”

Gaz presses a hand to her chin and furrows her brow. “Do you think you can actually, like,  _ transform _ or something?”

“I’ve thought about it, but if I can, I’d need to have the coat I was born with.”

“So hypothetically, if I found the coat and got you out of the house...you could escape into the ocean?”

Dib snaps his head up to stare at Gaz incredulously. “Wh- _ no, _ I’m not gonna leave you here alone—!”

“As shitty as it is to admit, dad prefers me over you because I just shut up and do what he expects of me. If he gets mad at me, he’ll get over it soon enough. I’ll be fine,” Gaz explains with a sour tone.

Dib scratches at his wrist as his skin starts itching again. “I’ll think about it.”

“I’m not giving you a choice, dipshit. I’m helping you because I’m worried you’re just gonna fucking die or something. I can tell you’re in a lot of pain and I hear you crying at night. It’s depressing.”

Dib flushes at her blunt comment about hearing him cry at night. He thought he’d been muffling it as best he could. He coughs awkwardly. “I don’t cry at night...”

“Cut the “I’m a manly man who doesn’t cry” bullshit, Dib. I know you cry because of the shit you’re going through and there’s nothing wrong with that. Cry if you need to. Doesn’t mean you’re less of a man or weak or something.”

Dib stops scratching his skin. “Th-thanks, Gaz. That means a lot to hear…”

“It’s whatever.” She rises to her feet and heads for the door. “You’re my brother, man. I bully you a lot because you can usually handle it. But right now, I’m just freaking out a bit. It’s on the inside like always, but I really am worried about you.”

“I’m sor—”Dib starts, but catches himself and revises his words, ”Thanks for checking up on me. It’s nice to know someone cares.”

Gaz gives a noncommittal grunt in response, but Dib can tell from the glint in her eyes that his words make Gaz feel good about her choices. She lingers a moment longer before leaving and quietly shutting the door behind her. 

The moment Gaz leaves, however, Dib is left alone with his thoughts. The aching in his body intensifies. With a frustrated groan, Dib grabs fistfuls of his hair and curls in on himself again as he tries to think of anything other than the sea.

And if he cries, only Gaz and himself will know.

* * *

Zim lets out yet another piercing whistle before sinking down so that only his eyes hover above the water’s surface. His antennae remain pricked as the icy wind buffets them back and forth and distorts his hearing, and despite the way they twitch in pain from the wind, Zim doesn’t move. His red eyes scan the shoreline 100 yards away, but he still sees no sign of his two-legged friend. 

An osprey passes over him a few times, perhaps wondering if Zim is dead, but when the siren hisses at the sky, the bird soars away along the shoreline. Zim blows air and water out of his gills in frustration. 

_ The Dib-beast still hasn’t returned. _

Despite his wariness, Zim slowly makes his way closer to the rocky beach. Once he’s close enough to be rocked around by the waves crashing into the shore, he fills his lungs with air and lets out another series of loud whistles. 

He waits. 

And waits. 

And waits some more. 

But his friend makes no appearance. 

Zim is no quitter, though. He flits closer to the shore and whistles again. Then he waits. Then he moves closer and calls again. He does this until he’s within arm’s reach of the shore, and he’s about to climb onto the sandy rocks when an answering chirp resounds from behind him. Zim turns his head.

Skoodge’s head bobs just above the water’s surface with somber red eyes. Zim curls his lip. 

“Zim does not need your  _ pity, _ Skoodge.”

Skoodge huffs. The chubbier siren moves to float beside Zim before placing a large, webbed hand on Zim’s thin shoulder. Zim hisses in warning but makes no move to attack his clutchmate. 

“I’m not pitying you, Zim,” Skoodge murmurs, “I’m sympathizing with you. Those are two very different things.”

“Not to me, they aren’t,” Zim mutters.

Skoodge heaves a sigh. “I’m worried about you. You went through a stressful experience and barely managed to escape. You haven’t let me help you come to terms with that. Not to mention the absence of the Dib-human.”

Zim slaps Skoodge’s hand off his shoulder, whirling around to bare both rows of jagged teeth at him. “I don’t need you to  _ remind me. _ I am  _ very  _ aware of the Dib’s absence.”

Skoodge narrows his eyes. “I’m just trying to help. It’s not  _ my _ fault the Dib is gone, so why are you acting like it is?”

Zim’s tail slaps the surface of the water in agitation. “Zim doesn’t know! Why am I so upset?! The Dib is just a stinky  _ human, _ and I never planned on being his “friend” in the first place! Why does…” Zim grinds his teeth together and presses a hand to his chest, “...why does Zim’s chest  _ hurt _ so much?”

“You miss him,” Skoodge replies simply, “You love him and miss him, and you’re worried he’s never coming back.”

Zim wants to shoot back a fiery retort, but instead he lets his shoulders slump and drops his head. A strange feeling rises in his throat, like he has a fishbone stuck there, and Zim swallows hard in an attempt to get rid of the feeling. But all that happens is that a strange noise begins rumbling in his chest and throat.

It’s something between a chirp and a purr, like a mournful chitter. Zim hasn’t ever heard this noise before, and as much as he’d like to stop it, he  _ can’t.  _ It just keeps coming, and his eyes burn. Zim rubs at them, but that only forces them to leak a clear liquid. “Wh-what is—”

Skoodge wraps his arms around Zim and hugs him tight. And for once, Zim doesn’t fight the gentle touch. Instead, he brings his thin arms up to return the gesture and lets the somber noise tumble freely from his throat.

At some point, Skoodge gently guides Zim back underwater and into the safety of their cave far offshore. The strange noises subside after a while, but Zim still feels like his throat is closing up, like there’s a hole in his chest that won’t fill itself back up. 

Once they retreat into the cave they share, Zim and Skoodge separate. Skoodge moves to the rocky outcroppings he uses to store his enchanting tools and ingredients at the back of the cave, and Zim curls up bitterly on his bed of kelp and seagrass. 

Zim would like it if he could just forget all the time he spent with Dib, if it would mean this foreign feeling would go away, but at the same time, he doesn’t  _ want _ to forget. He wants to treasure the days he spent playing with the human, to relive them over and over and over again. His claws dig into the seagrass below him. 

_ I want him back. _

“You know…” Skoodge starts, which makes Zim look at him miserably “...I’m sure there’s a way to find him.”

Zim snorts. “ _ How,  _ exactly?”

With a cocky smirk, Skoodge ducks down and rummages in the storage pits below his supply shelves. The sound of clanking metal and rattling pebbles piques Zim’s curiosity, and the siren cranes his neck to peer at what Skoodge could possibly be doing.

“A-ha!” Skoodge chirps, and Zim swims over to see what’s got him so excited.

Zim barely ducks out of the way as Skoodge whirls around with a large, hollow sphere of metal in his webbed hands. For a few moments, Zim squints at it. His eyes drift over to meet Skoodge’s. “How in all the seven seas is this chunk of human trash supposed to help find the Dib?”

“Oh, I have an idea of how to make it useful. Trust me.”

* * *

Gaz steps into the hallway on silent feet.

The house is dark, and not even the moon’s silver light can filter in through the covered windows. It’s a depressing sight, and Gaz is certain this is enough crazy sheltering to affect a  _ human _ . She lets a quiet breath slip through her lips. 

_ I’ll spend an hour looking, then I’ll try again tomorrow night. _

So Gaz begins searching in silence, first checking the spare bedroom, then the living room, and then the kitchen. The clock ticks onward in an uncaring manner, and Gaz starts to resent the sound of it in the kitchen. It mocks her struggle to help her brother, and Gaz has never liked being mocked. 

But she suppresses the urge to drive her fist into the taunting face of the clock and continues digging through drawers, cupboards, and closets in search of anything even  _ vaguely  _ resembling a Selkie coat. And while she’s never seen one herself, a quick Google search brought up thousands of results. Most of them were hand-drawn diagrams by cryptid enthusiasts, but Gaz supposes they must be at least  _ somewhat _ grounded in reality. So she formed her own mental image of what it’d look like, and hopes it isn’t too far-off. 

Her self-imposed 3AM curfew is almost upon her when she becomes aware of a new noise. She pauses, straining her ears. 

_ Thump. Thump. Thump. _

Gaz lets out a soft breath and tries to pinpoint where the sound is coming from. It doesn’t take her long to figure out that it’s coming from above her, from her brother’s room. She reluctantly acknowledges that her brother’s current state is more important than her self-appointed mission, curses softly under her breath, then makes her way quickly and quietly back upstairs to Dib’s bedroom door. 

“ _ Dib!”  _ she hisses under her breath. The soft noise stops. 

Moments later, the door opens and Gaz finds herself looking into the exhausted face of her brother. Dark bags hang heavily under his eyes, his skin is ghostly-pale, and there’s a tremble in his fingers that Gaz has only ever seen in the elderly and the chronically-ill. 

“Gaz?”

“What are you doing?” she whispers with a fleeting glance over her shoulder at the professor’s door. 

Dib glances past her at the door as well before stepping aside to let her in. 

Her eyes almost immediately lock onto the walls around Dib’s window. 

“Look, I…” Dib sighs, “...I just need some air or I’ll go insane.”

It looks as though a rabid raccoon clawed its way out of the drywall, leaving a scraped-out hole directly to the insulation inside. A pile of fine drywall dust litters the hardwood along the baseboards, and when Dib casts a pensive look at Dib, she can see the same drywall dust caked under his nails. 

“Dib, I totally understand that you’re honestly losing it here,” Gaz begins before gesturing to the hole in the wall, “but couldn’t you have used a fucking knife or something instead of your nails?”

“Oh. Yeah, I guess I could have,” Dib replies in an odd tone, like he hadn’t even thought of that before.

Gaz furrows her brow in concern and takes another look at her brother. And now that she  _ really _ looks at him, she can see a faraway, desperate look in his eyes. It reminds her of a caged animal, of the squirrel she caught with a snare in the attic as a child. It’s a haunted, trapped look, and Gaz hasn’t seen a human look like that before. 

It’s unnerving, and sends a chill up her spine. 

“Okay. Just...cover that up with a poster or something, alright? Who knows what dad’ll do if he sees you scraping holes in the walls?”

Dib’s face darkens. “I don’t care what he thinks. Or what he’ll do. It’s his fault.”

Gaz grabs his wrist abruptly and glares into his face. He meets her gaze with an uncharacteristically feral one of his own, but Gaz doesn’t break eye contact as she snarls, “ _ You _ might not care, but  _ I _ do, you dumbass. I have to see you looking like a walking corpse on a daily basis, and I don’t want to see you become an  _ actual _ corpse. So cut the shit already, or I’ll cut it for you.”

The fire in Dib’s eyes dies and he cocks an eyebrow in confusion. “That doesn’t make any sense—”

Gaz punches him in the arm. “I don’t  _ care.  _ Just knock it off.”

“Okay, fine! Jeez!”

Gaz lets go of Dib’s arm and backs away towards the door with a scowl. Before she leaves, she holds two fingers up in front of her eyes and turns her hand to point them at Dib. The universal signal for  _ “I’m watching you.” _ Dib rolls his eyes. 

Gaz leaves the room, shutting the door behind her before letting out a quiet groan and going to her own room. 

_ I need to find this stupid coat, and fast. _

* * *

Membrane hasn’t so much as glanced at his son since the day they fought. He hasn’t been able to bring himself to look at Dib, not if he wants to avoid yelling at his son again. His anger, his betrayal, his reopened wounds, they all run the risk of making an appearance if Membrane wants to talk to Dib.

But now, after a month has passed, the burning anger has subsided into mild irritation. Membrane finally feels it’s safe to talk to his son, and there will be no risk of accidentally losing his temper. 

As he descends from the lab and makes his way towards Dib’s bedroom door, he’s surprised to see Gaz step boldly out of her room and place herself between Membrane and Dib’s door. Her arms are folded across her chest, brows furrowed. The professor cocks an eyebrow.

“Gaz, dear, what—”

“You sure you wanna see what you’ve done?” Gaz interrupts flatly with an accusatory glare.

Membrane scratches awkwardly at the side of his neck. “What do you mean?”

Gaz clicks her tongue. “You ever read that legend about the Selkie and the human who hid her coat from her?”

“N-no, I have not—”

“Read it,” Gaz snaps, “It’s a 30-second google search.”

With that, she wedges her hands in the pocket of her sweater and stalks off down the hall. Before she vanishes into her room, however, she pauses with one hand on the doorknob. Her amber eyes burn holes in the professor’s head as she growls, “You think you’re in the right here, but you’re the bad guy. I’m tired of it.”

Her door slams shut behind her. Membrane stares at it in dumbfounded shock as her words start to sink in. A thrill of fear races through the professor’s body and he moves to open Dib’s door. 

“Leave me alone,” Dib hisses from inside.

The professor takes a deep breath. “Son, I just want to talk—”

“I don’t want to talk.”

“Please?”

“Maybe if you treated me like a fucking human and not a zoo animal I’d be willing to talk, but that ship sailed a month ago.”

Membrane winces. He turns the knob. 

The boy before him sits cross-legged on the bed in the dark room with cold, mistrustful eyes. His clothes and glasses are still just as clean and scent-free as always, and he hasn’t lost weight, but the sight of him still makes Membrane’s blood turn to ice.

There’s a tremble in his hands that won’t quit, shadows under his eyes, and his skin has gone white. His nails have been chewed down to their beds, and the skin on his arms is raw and red with scratch-marks. This boy is...this boy is completely different from the son he’d dragged home from the beach a month ago. 

“I said I didn’t want to talk.”

“I think we need to talk, though.”

Dib barks out a humorless laugh. “You only want to talk because you want to clear  _ your  _ conscience. When we’re done, you’re just gonna leave me here, cut off from the world, until the day I die. And you’ll think you were the hero for “saving” me from the outside world.”

Membrane shivers. He feels like he’s looking into the eyes of a cornered, defeated animal...and perhaps he is. 

It hits him then, what Gaz had said. 

_ I did this.  _

He takes a few steps back, eyes wide. 

His mind flits back to the journals he’d written all those years ago, and the words he’d said to Catherine in the quiet minutes they shared before sinking into sound slumber. He’d promised her...he’d promised he’d never be the source of his children’s pain. He swore he’d be a truly good parent, a parent who was present for their children, a parent whose children could rely on them. 

_ I broke my promise. _

The professor turns and leaves the room in a hurry, slamming it behind him. His breath comes in ragged gasps, sweat beads on his skin, and shivers rip through his body. He presses a hand to his face as he stumbles across the hall to his bedroom. 

_ I became an abusive parent. _

_ I became what I swore to never become.  _

A choked noise escapes him, but he holds back the tears that well up in his eyes. 

_ I  _ am _ the villain here. _

* * *

“What is it?” 

“Come here, I’ll show you.”

Several days have passed since Skoodge began tinkering with the hollow metal sphere, and it scarcely resembles the dented piece of trash it started as. 

The metal shimmers pale purple when the light hits it just right, the hollow centre has been filled with repurposed human garbage and various trinkets, and the three openings in the sphere’s surface have been patched shut with smooth stones and shells. Almost the entire device has been enchanted, and because of that, the interior gives off a pale pink glow that reflects off both Skoodge and Zim’s scales.

Zim extends a claw to tap the device in Skoodge’s hands curiously. “What is the point of this device?”

“Follow me,” Skoodge says without further explanation, leaving the cave as Zim stares after him.

Zim huffs in annoyance, but follows the smaller siren out into the open anyways. And Skoodge leads him quite a distance; they pass the rocky beach where Zim and Dib have their meetings, winding along the shoreline in such a random manner that Zim almost thinks Skoodge is messing with him. 

That is, until Skoodge approaches a small, sandy beach beneath a towering stone cliff. He swims nonchalantly into the shallows, and Zim follows him anxiously, red eyes scanning the surrounding area for any sign of another trap. Nothing dangerous shows itself, so Zim tries to relax and focuses his attention on Skoodge. 

With a puff of effort, Skoodge pulls himself up to sit on the damp sand at the water’s edge and gestures for Zim to follow. Zim complies tentatively. 

“This device will help you look for the Dib, but the first use will cause some pain and discomfort, I imagine.”

Zim clicks his tongue. “Zim is no  _ smeet!  _ Show me how it wORKS-”

Skoodge presses the flat side of the device to the centre of Zim’s back and Zim shrieks in alarm as something creeps out of the device and forces itself into the gills on both sides of his ribs. His hands fly up, claws reaching for the device’s tendrils, but he freezes when his tail begins to itch. His sense of hearing grows less sharp, his second row of teeth vanish, and his tail splits down the middle. 

Zim watches in astonished wonder as he shifts from siren...to  _ human. _

* * *

Gaz is once again searching the house in the dead of night. 

Her hour of searching has scarcely begun, but she’s already torn apart the main floor and found nothing. She groans inwardly as she shoves a pile of moth-eaten winter jackets back in the hall closet. 

_ I didn’t even know we  _ had _ winter jackets in here. _

Once she’s wrestled the jackets into submission and shoved them roughly into the closet, she rises to her feet, takes a swig of the Monster drink in her hand, and starts for the stairs. Her hands shake from the mingled exhaustion and energy coursing through her, but she walks steadily up the stairs with a determined scowl on her face.

As she’s about to open the closet in the second-floor hallway, Gaz pauses. 

_ The lab. Of course! _

And there’s only one part of the lab that it’d be hidden in. The one place Gaz has never laid eyes on, and the one place her father would never expect her to get into. 

The lab’s inner belly. 

A quiet breath leaves her lips. She turns on her heel and returns to her room, shutting the door behind her and approaching her gaming corner. As quietly as she can, she opens her desk’s drawers and starts rummaging through the ridiculous tools and devices she’s thrown together over the years. 

Gaz had a feeling her secret tinkering hobby would come in handy someday. 

Finally, she finds what she’s looking for: an old GameBoy with two metal prongs sticking out of its top edge. She flicks it on, and the familiar rainbow logo dances across the screen. But instead of opening to a game, the screen flickers and displays several options.

**FIND SIGNAL || ACTIVATE TASER || PLAY GAME**

Then, at the bottom of the menu:

**OVERRIDE SECURITY PROTOCOLS**

Gaz turns down the volume on the device to zero and lets out a nervous breath. This is the ultimate act of rebellion against her father, and that frightens her. She knows the professor would never lay a hand on her or Dib, but something deep within her soul protests against her decision to help Dib. It implores Gaz to go back to bed, to drown out the noise and thoughts, to wait for the storm to pass so she can pretend everything is fine. 

For the first time ever, Gaz reaches back and crushes down that little voice. She refuses to be complacent anymore. Her father is tormenting Dib whether he realizes it or not, and if Gaz is picking sides, well, she’s going to help Dib.

She narrows her amber eyes and stalks out into the hall. 

Her feet make no noise at all as she walks past her father’s room and up the metal stairwell leading to the laboratory. She’s silent pushing open the door to the outer laboratory, but once she’s inside, she doesn’t worry as much. 

The professor soundproofed the entire lab, so unless she’s in the stairwell, no sound will reach the lower floors. 

Gaz pauses in the middle of the lab and slowly turns her head to glance out the large windows that wrap around the dome that encapsulates the room. The moon reflects off the sea in silver shards of dancing light, and a salt breeze drifts through a slightly-open window pane. Gaz takes a deep breath through her nose, eyes closed, and holds it for a time before letting it leave her slowly.

Something inside her stirs in its sleep.

_ “Oh.” _

Gaz is more human than Selkie, and thus she can never truly understand how her brother feels, but for a fleeting moment...she feels it. The teeth of some fierce creature dig into her gut and  _ pull _ in the direction of the ocean. It thrashes and writhes and shakes its head, trying to awaken something even more primordial from slumber, but as quickly as the feeling arises, it vanishes. Gaz is left with a pounding heart, shaking fingers, and wide eyes. Her hands white-knuckle grip the device in her hands, and she has to take a moment to calm herself down.

_ What the fuck. _

She lets go of her device with one hand to push her hair away from her face with a shaky sigh. Then, with one last nervous glance at the ocean, she turns away and approaches the door to the inner sanctum. 

_ I can think about that Selkie shit later. I have something important to deal with first. _

Once she’s in front of the heavy metal doors, her eyes drift down to the keypad on the left side of them. Her hands still shudder from the odd feeling she’d just experienced, but she manages to activate the device in her hands. The two prongs extend out from it, and from them shoot forth two fine wires that attach to the keypad with two shitty magnets Gaz got from the dollar store. 

But they do the job they were intended for, which is to hold the wires in place as the device sends out a signal. The device hums for a bit as it tries to bypass the security protocols, but before long it beeps twice and displays an error message. Gaz sighs in exasperation.

_ Okay, I should’ve known dad’s firewalls were better than my stupid machine. _

So, she decides to go about it the old-fashioned way. 

Gaz squints and brings her face close to the keypad while letting the light from her device’s screen hit the buttons. And when the light hits them, Gaz grins. 

Two keys are worn from use, all the texture rubbed from them and letting the light reflect freely off their surfaces. Gaz notes which keys are worn down—9 and 8—and how many digits the code itself is—4 digits—and punches them into her device. She scrolls down the menu and hits an option. 

**FIND ALL PERMUTATIONS?**

Gaz hits “yes.” A wall of number combinations fills the screen. Gaz sits down on the floor in front of the keypad with crossed legs and reaches into her pocket for a fresh piece of gum. 

“Guess I’m gonna be here for a while…”

* * *

Dib wakes up to something warm and heavy covering his face.

With a frustrated groan, he shoves it off onto the floor and jumps in surprise when he hears paper hit the floor as well. He flicks on the light to illuminate his dark room…

...on the floor is a grey-and-white fur coat peppered with black spots. A yellow piece of notebook paper has been attached to it. Eyes wide and jaw dropped, Dib reaches across to snatch his glasses from his nightstand. 

He grabs the note and holds it up to his face.

**Hey, shithead. Found the coat. Dad hid it in the inner lab and I was up til 6 this morning testing codes to get in. You owe me. When you get a chance to escape to the ocean though, don’t die or I’ll fucking kill you.**

**-Gaz**

With shaking hands, Dib reaches over the edge of his bed to pull the coat into his lap. He runs his fingers reverently over its surface, and something wild inside him starts to thrash about. He lets out a shaky sigh. Dib wraps his arms around it and hugs it to his chest, burying his face in the soft coat.

_ This is my ticket out.  _

_ I’m going home. _

* * *

At breakfast the following morning, Membrane knows something is amiss. 

Dib isn’t coming to eat, which isn’t new, but Gaz doesn’t so much as look at her father. Beneath her eyes are dark rings, and while Gaz often spends her nights gaming, she always makes sure she has enough sleep. The professor considers commenting on it, but before he can, his daughter’s words from the other night hit him and he decides to remain silent. 

Her words had hit him like a freight train and blew his entire perception of the situation into smithereens. Not only that, but the  _ look _ she’d given him was absolutely harrowing. Membrane’s never seen Gaz look at him like that, with betrayal and anger and pain on full display, but he already knows he never wants to see that on her face again. 

Then there’s Dib. The professor heaves a sigh and places his fork down on the table as nausea bubbles in his stomach. Only then does Gaz let her gaze drift up from her plate of eggs. 

Now, the professor notices something new there. Something that wasn’t there when he saw her last night. 

It’s not as prominent as it is in Dib, but there’s a vague glimmer of something animalistic behind her amber eyes. 

_ That’s the same look Catherine had. _

He swallows. 

“Something wrong, dad?” Gaz asks flatly, as though she’s being forced to ask.

The professor runs a hand through his hair with a sigh. “I’ve just been...reconsidering things. Taking a look at myself from a different angle.”

“‘Bout time.”

“Yes, I suppose it’s long overdue.”

Gaz watches him in silence for a while longer before looking back down at her food and shoveling some hash-browns into her mouth. The silence stretches longer and longer, growing taut as a piano wire, and as it does, the professor lets his mind run amok. 

He needs to fix this. He needs to fix the relationship with his children, to fix  _ himself, _ or he’ll lose them in a different way. Dib and Gaz, for all the traits they share with their mother, are  _ not _ Catherine. Catherine is gone, as painful as it is to admit, and she’s never coming back. However, a piece of her lives on in each of her children, and Membrane realizes he’s let that small piece of her completely overshadow the fact that they aren’t her. 

_ Gaz and Dib are their own people,  _ he thinks firmly,  _ I need to acknowledge that.  _

“Gaz, dear, I…” Membrane begins haltingly, “...I am sorry. For how I’ve treated you, and for not being present in your life. I have been a bad parent, I realize this now, and I would like to try making up for it.”

Gaz pauses. She raises her head to look at Membrane full-on. 

“You serious?”

“I am dead serious.”

“Huh,” Gaz hums, “I appreciate the apology and all, but I think we both know who you  _ really  _ need to apologize to.”

The professor nods. “Indeed.”

Fork spinning slowly between her fingers, Gaz rests her head on one hand and smirks in her father’s direction. “You’ve got a hell of a lotta shitty parenting to make up for in Dib’s case.”

Membrane winces. “I see that now, and—”

“You promise you’ll do it?”

“Pardon?”

Gaz sets her fork down firmly. Her brows lower over her eyes and she speaks in a severe tone. “You’d better promise to treat Dib and I like actual people. No bullshit half-promises. No saying “I will” and then dropping the ball on it.”

Membrane opens his mouth, but no sound comes out. Gaz’s frown turns into a scowl. 

“Because you have  _ no fucking idea _ how close you are to losing Dib. Unless you shape up, he’s going to leave and never come back.”

Her words send a chill up the professor’s spine, and he finds it hard to meet her burning glare. But he does, and with a level voice he replies, “I promise. I’m going to be a better father. And I will strive to be a parent you can both be proud of. Until my dying day, I will try.”

Gaz holds his gaze for a short time longer, then lets out a huff of laughter. “ _ Christ, _ I thought I’d never see the day you admitted you were wrong. It’s a cold day in hell.”

“While I’m happy to see you happy, I would appreciate it if you would watch your language somewhat. You’ve gotten quite the colourful vocabulary over the years.”

“Now  _ there’s  _ a responsible parent,” Gaz snorts, arms crossed, “But nah. I think I’m entitled to a bit of nasty language.”

“I suppose that’s fair.”

“Fuck yeah, it is.”

* * *

_ Scritch. Scritch. Scritch. _

Dib stirs.

_ Clunk. Scritch. Scritch. _

His eyes flutter open.

_ Scritch. Scritch.  _

“What the fu—”

_ THUD! _

Dib sits bolt upright in bed, having fallen asleep a few minutes earlier hugging his coat to his chest. His glasses are skewed crookedly across his face, a trail of drool runs down his chin, and his hair is flattened to one side of his head. All in all, he’s not a nice sight.

But what  _ is _ a nice sight is the beam of brilliant morning light that shines through a round hole in the wall next to Dib’s window. Dib rubs at his eyes and swings his legs over the edge of his bed, muttering incoherently as he moves to inspect what the  _ hell _ could’ve made the hole.

He leans close, hoping to at least feel a bit of sun on his face. 

Wide purple eyes pop up directly in his face.

Dib muffles a shriek as he leaps away and falls on his ass. Whatever creature surprised him is silhouetted against the light flooding into the dark room, but the voice is unmistakable.

“Dib-beast!”

Dib sits up with wide eyes. “Zim?!”

Zim crashes into him, knocking him back to the floor, and the siren wraps his skinny arms around Dib’s shoulders. With an incredulous laugh, Dib returns the embrace and fights back the urge to cry with happiness.

When the initial euphoria fades, Dib’s reason comes back to him and he adjusts his glasses to peer into Zim’s face. “How did you—”

Zim grabs Dib’s cheeks, and before Dib can process what’s happening, Zim’s cold lips smash into his mouth. Dib squeaks in surprise and almost pulls away, but he doesn’t have a chance. Zim pulls away before Dib can with an exaggerated gasp, “ _ Disgusting!  _ Human courting rituals are gross!”

“Wh-what the...Zim, you can’t just  _ kiss someone _ out of nowhere and—”

“Well, Zim did! And now since we are a mated pair, I am bringing you to the sea! Your father-unit is a rabid creature and cannot be trusted with my ma—”

Dib holds up his hands to hopefully halt Zim’s tirade. “Whoa,  _ whoa,  _ what do you mean, “mated pair?” What the fuck? Why do you have  _ legs, _ and—”

Zim shushes him and presses a clammy hand over Dib’s mouth. “Shut up, Dib-smell! Zim will answer your questions when we are in the sea! Skoodge, my...er... _ slave-friend-companion- _ thing...whatever you call him, he can enchant you a device! A wonderful device, made to allow your pitiful human  _ lung-bags _ to breathe underwater—”

“ _ Zim,”  _ Dib says insistently, and Zim finally shuts his mouth. 

Dib rises to his feet, and Zim follows with a curious look on his face. They cross the room to Dib’s bed, and with a smile, Dib pulls the Selkie coat from where it lies on his bed and holds it up to show Zim. Zim stares at it blankly.

“Human fashion is outlandish at best.”

“No, you  _ cabbage, _ it’s my coat! So I can become a—”

“Oh!” Zim exclaims, “So you can become the seal-beastie!”

Dib nods. Zim bares still-jagged teeth in an excited grin. 

“Excellent! Now let’s go! Before the father-beast smells my delicious siren blood!”

“Never call yourself delicious again.”

Zim grabs Dib’s face again, which Dib is slightly more prepared for, and stares into the human’s eyes seriously. 

“Zim knows humans have much different courting rituals than sirens, and that is fine. Sirens form attachments to potential mates much quicker than humans tend to, and so I understand that you do not yet feel the same way I do. But!” Zim lets go of Dib’s head, “But Zim would like to court the Dib properly when we have departed for the sea! Will you be comfortable with Zim’s advances?”

Dib blinks owlishly. “Wow. That’s one hell of a confession.”

“Do  _ not _ ruin the mood for me, Dib.”

“Chill, man,” Dib laughs, “But yeah, I’d be fine with you doing that. I mean, I like you well enough already, so—”

The door opens. Zim and Dib snap their heads around to look.

The professor and Gaz stand in the door with wide, shocked eyes.

* * *

Everyone freezes for a few heartbeats. 

The professor takes in the scene before him: a boy with green skin and a pink tunic standing next to Dib, whose eyes have regained the life they lost. A perfectly circular hole in the wall next to the blocked window. The smell of seawater. 

In Dib’s hands, a Selkie coat.

“ _ Go!”  _ the green boy snaps.

Membrane opens his mouth to shout, taking a hurried step forward. Dib slips through the hole in the wall. The professor reaches out to grab the green boy. Gaz slips between the professor and the boy with her arms spread out at her sides. 

“Gazlene, what are you—?!”

“Let them go.” Gaz says.

The green boy darts out into the morning sun.

Brain running on autopilot, Membrane whirls around and tears down the hall, down the stairs, and out into the backyard. The boys have already made an impressive amount of distance through the saltgrass hills as they race for the sea. Membrane curses under his breath and yanks off his gloves. 

They’ve hardly hit the ground before Membrane activates his cybernetic arms. The rockets in them growl to life, lifting him into the air as he continues his pursuit of the two boys. 

They reach the sandy beach. The professor is a hair’s length from being able to grab Dib’s shirt. 

_ He’s not Catherine. _

The professor stops. 

Dib and the green boy keep running for the surf, and sparkling drops of icy water drench their clothes as they hit the shallows. Membrane deactivates the rockets in his arms and lands quietly on the sand. 

_ Let them go,  _ Gaz’s voice echoes in his head.

Dib and his friend must’ve heard the sound of rockets fading, because they stop in waist-deep water and glance back at the professor. For a time, nothing happens. 

Membrane takes a shaky breath and gives his son a curt nod. 

Dib sees it. 

His face bursts into a smile Membrane can see even from this distance, and he pulls the coat over his shoulders. 

They vanish into the sea like they were never there at all. 

The professor drops to his knees in the sand, and lets the tears fall.

* * *

**_The following summer_ **

“Oh, shit, check this one out.”

“Language, Gazlene.”

Wearing an oversized black  _ DOOM _ t-shirt, Gaz kneels beside a shallow tidepool under the pink-and-gold sunset sky. Unable to see what she’s reaching for, Professor Membrane walks leisurely along the beach in her direction. He’s swapped his signature white lab coat and black gloves for a gaudy Hawaiian shirt, cargo shorts, and Crocs. And while he  _ does _ feel quite silly in these clothes, Gaz picked them out and they  _ are  _ quite comfortable. 

Gaz turns to face the professor with one of her half-smiles she’s started to show off more often. In her hand is a tiny reddish-brown octopus. With an intrigued hum, the professor kneels next to Gaz and inspects the little creature.

“Ah,  _ octopus joubini!  _ The Atlantic Pygmy Octopus!” Membrane exclaims. “An intriguing little organism indeed! Excellent find!”

Gaz grunts, a noise Membrane recognizes as a good thing. She appreciates his interest, and knowing that makes a warmth blossom in his chest. He watches as Gaz gently puts the octopus back where she found it and wipes her slimy hand on her shorts. 

The professor rises to his feet and moves to the next tidepool, careful to keep an eye on the slowly-rising tide. He walks along the edge of the pool, eyes scanning the rocks and flora for any sea life. 

This has become a routine “thing” with the professor and his daughter; their family counsellor recommended spending at least two or three evenings a week with each other in order to start repairing their rocky relationship. And after eight months, things have been going incredibly well. Gaz talks to Membrane about things that concern or interest her, and he, in turn, talks to her about the same things. 

But Membrane’s favorite nights are these ones. These are the nights where he doesn’t need to think about work, or the grief he’s slowly learning to work through, or anything. He can merely  _ exist _ and  _ enjoy _ himself. 

The sea, as well, has gone from a terrifying, lurking beast to a comforting constant in the professor’s life. 

While it still frightens him as it should frighten any human being, it’s not an active threat to him anymore. It’s merely a fact of life; a vast alternate reality that exists at his doorstep and laps meekly at the sand. And he’s come to associate it with Catherine and Dib. It is a part of them both, and while the professor knows he may never see his son again, he’s happy knowing he made the right choice to let Dib go. It’s a bittersweet feeling.

Movement catches his eye in the tidepool and he leans over to inspect it. With a chuckle, he picks up a little crab. 

“I found another!” Membrane calls to Gaz, who pokes her head up from the other side of a mussel-coated boulder. 

He holds up the crab as she moves closer to check it out. When she’s close enough, the professor asks, “Do you know what species this one is?”

He’s hoping she’ll take a guess, and he’s confident she knows what species it is. So it takes him by surprise when she shrugs and says, “No frickin’ idea.”

Membrane laughs at her blunt answer, placing the crab back in the tidepool. “It’s an honest answer, I suppose!”

They watch the crab scuttle away under the rocks in companionable silence, and the professor reaches over to gently squeeze his daughter’s shoulder. The corner of her mouth quirks upward for a moment. Membrane smiles.

And he’s just about to suggest they head home when a voice comes from behind them, from the direction of the sea.

“Nice shirt. I bet they can see you from the International Space Station with a color scheme like that.”

The professor’s heart stops. 

He and Gaz exchange a shocked look before slowly looking back at the source of the voice. 

Standing there in a drenched blue t-shirt and shorts, with a Selkie coat draped over his shoulders, is Dib. 

His hair is a couple inches longer than it was when he vanished into the ocean, and he has a strangely-engraved shell on a cord around his neck, but he looks healthier than he’s ever been. The professor’s certain Dib’s gotten noticeably more muscular than he’d ever expected, and his skin is tan rather than pale. 

Gaz and the professor leap to their feet in unison. Dib snorts in amusement, and holds up something he’d been gripping in one hand: a glass bottle with a rolled-up letter inside.

“Got your letter, Gaz. I mean...it took a while, but it’s not exactly as easy as sending a text,” Dib says with an awkward smile. “I guess you guys have been going to a counsellor? And that a lot of the issues have been worked out? That’s what the letter said, at least…” he trails off, “...I, uh, I figured I’d visit and see how things are going? And maybe eat something other than fish. It gets bland after a while.”

Dib’s rambling probably would’ve gone on for a good while longer, but the professor approaches him with his lips set in a line. Dib’s eyes flash with alarm behind his water-stained glasses, but other than that, he shows no outward signs of fear. Membrane stops in front of Dib, still not saying a word, and they hold each other’s eyes for a few moments.

Then, the spell is broken and the professor wraps Dib in a massive hug, pulling the soaked boy close. Dib remains stiff as a board in his father’s arms, and the professor is slightly concerned that his son will run away again, but after a while Dib awkwardly returns the gesture. 

“My son, I am so sorry for everything I did to you,” Membrane says around the lump in his throat, “I was wrong, and I can never erase the trauma I caused you...but just know that you are always welcome in my house. You will never be held captive or hurt by my hand again. You may come and go as you please. I promise.”

“Dad, I—”

“And if you never wish to return, that is your choice and I will not impede you,” he continues, giving Dib a brief squeeze before letting him go, “But if you will give me another chance, I assure you I will not let you down, my boy.”

Dib meets his father’s eyes, and the professor feels like his son is looking at his very soul, peeling away its layers and judging what he finds at its core. And the professor is worried about what Dib might see there. But with a deep breath, Dib runs a hand through his hair and laughs, “Wow, that’s...wow. You’re serious?”

“He’s dead serious, kelp-brain,” Gaz replies flatly.

“Oh. That’s...damn, I never thought you’d…”

The professor chuckles. “That I would realize I’m a poor excuse of a parent?”

“I wouldn’t say that—” Dib backpedals with an awkward wave of his hands.

Gaz barks out a laugh. “Oh, you can say it. It’s cool. He’s not a bad dude  _ anymore, _ though.”

The tension melts from Dib’s shoulders, and he removes the Selkie coat from his back. The simple gesture speaks volumes in the professor’s mind though—he recalls Catherine telling him once that Selkies will only fully remove their coats if they trust everyone present. And just knowing that Dib is going to let him try to be a better parent is enough to reignite the warmth in his chest. 

“Before we head home, though, I think I should introduce you to someone,” Dib says, dragging Membrane out of his quiet introspection. 

With a smile, Dib glances back over his shoulder and shouts, “You can come out now!”

After a moment, the green boy Dib had escaped with steps anxiously out from behind a boulder. Instead of a tunic, he wears an oversized t-shirt and black leggings, and a strange little backpack glows from between his shoulderblades. 

And now, up close, when Membrane really gets a good look at him, he recognizes exactly who the strange boy is. 

_ The siren that I— _

“Dad, Gaz, this is Zim.”

* * *

**Notes for the Chapter:**

> WOW this was incredibly fun to write!! Thank you so much for reading, and I hope you guys enjoyed this little three-shot fic!! 
> 
> I realize that this went from "silly siren au" to "a broken family learns how to heal and process grief, but with some supernatural elements sprinkled in" but to be honest, I'm really proud of this little story. No idea where the idea of a neglectful parent acknowledging and working to fix their mistakes came from but I'm not gonna complain. Membrane is a shit parent in the canon universe, and while I like to see him portrayed just like that, I think something in me just wanted something I never got in my actual life and the fic followed that mindset.
> 
> But I hope you guys liked this fic!! Thanks again to my friend Dramance for beta-reading all of this for me and keeing my motivation up, and thanks to all of you for following the updates, commenting, and leaving kudos! I'll see you around!! <3

**Author's Note:**

> Thanks again to Dramance for beta reading this for me!
> 
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